Name_________________________________________ Date______________ Period_________ Ch 1 & 2 These 3 questions refer to Substance Q, for which the solubility of Q is 99.2 g/100 g water at 50.0°C. 1. How many grams of water are needed to dissolve 43.7 g of Q at this temperature? [ANS = 44.1 g] 2. The solution in (3), above, is cooled to 20.0°C, where the solubility of Q is 75.5 g Q/100 g water. How much Q crystallizes out of solution? [ANS = 10.4 g crystallizes since 33.3 g can dissolve @ 20°C] 3. A homogenous solution of substance Q is made from 29.0 g of Q and 35.0 g water at 50°C. The solution is (unsaturated, saturated, supersaturated)? [ANS = unsaturated since 34.7 g Q could dissolve in 35.0 g H2O at 50°C] When the temperature drops 12.2 degrees Centigrade (Celsius) what is the final temperature (in degrees Fahrenheit) if the starting temperature was 14.3 degrees Fahrenheit? [ANS = -7.65°F, go into °C then subtract 12.2°C then go back to °F] The circumference of the earth is about 2.50 x 10 4 miles. What is the approximate radius of the earth in kilometers based on the information provided? (1 mile = 1.609 km) [4.02 x 10 4 km] A student was asked to find the density of an unknown liquid. The following measurements were made in a laboratory at 20 o C. The student saw 71.000g on the balance when weighing the flask and stopper empty, but wrote down 71 g rather than recording all of the zeroes. Mass of empty flask plus stopper: 71 g Mass of stoppered flask plus liquid: 128.125 g Volume of “calibrated” flask: 63.021 mL Be sure to use the correct number of “significant figures” according to the student’s results. 1. Calculate the density of the liquid using the data in the box above. [ANS = 0.91 g/ml] 2. What is the density of the unknown liquid when using the more precise value of 71.000 g for the first measurement? [ANS = 0.90644 g/ml] Last Updated: 8/21/22 Page 1/46
These 3 questions refer to Substance Q for which the solubility of Q is 992 g100 g water at 500degC
1 How many grams of water are needed to dissolve 437 g of Q at this temperature [ANS = 441 g]
2 The solution in (3) above is cooled to 200degC where the solubility of Q is 755 g Q100 g water How much Q crystallizes out of solution [ANS = 104 g crystallizes since 333 g can dissolve 20degC]
3 A homogenous solution of substance Q is made from 290 g of Q and 350 g water at 50degC The solution is (unsaturated saturated supersaturated) [ANS = unsaturated since 347 g Q could dissolve in 350 g H2O at 50degC]
When the temperature drops 122 degrees Centigrade (Celsius) what is the final temperature (in degrees Fahrenheit) if the starting temperature was 143 degrees Fahrenheit [ANS = -765degF go into degC then subtract 122degC then go back to degF]
The circumference of the earth is about 250 x 104 miles What is the approximate radius of the earth in kilometers based on the information provided (1 mile = 1609 km) [402 x 104 km]
A student was asked to find the density of an unknown liquid The following measurements were made in a laboratory at 20oC The student saw 71000g on the balance when weighing the flask and stopper empty but wrote down 71 g rather than recording all of the zeroes
Mass of empty flask plus stopper 71 g
Mass of stoppered flask plus liquid 128125 g
Volume of ldquocalibratedrdquo flask 63021 mL
Be sure to use the correct number of ldquosignificant figuresrdquo according to the studentrsquos results
1 Calculate the density of the liquid using the data in the box above [ANS = 091 gml]
2 What is the density of the unknown liquid when using the more precise value of 71000 g for the first measurement [ANS = 090644 gml]
Suppose a student has copper (II) nitrate and Fe(NO3)3 in her unknown sample in the Paper
Chromatography lab in this course She identifies them using her known solutions and calculates
the Rf values for each metal ion The solvent moves 72 cm during the experiment The R f value
for the copper (II) nitrate is 046
1 What is the formula for copper (II) nitrate
2 What is the name for Fe(NO3)3
3 The Fe ion traveled 53 cm up the paper during the experiment What was its R f value
4 How far did the copper ion travel up the paper during the experiment
5 If the experiment had been carried out twice as long with taller filter paper which of the
(a) Both Rf values would increase and the ions would be further apart at the end
(b) Both Rf values would decrease and the ions would be closer together at the end
(c) The ions would be further separated because the larger Rf value would get bigger and
the smaller Rf value would get smaller
(d) The Rf values would remain constant and the ions would be further apart
(e) The Rf values would remain constant and the ions would be closer together
[ANS = Cu(NO3)2 iron(III) nitrate 074 33 cm d]
The solubility of Li2SO4 is 31 g100 g H2O at 80ordmC and 35 g100 g at 20ordmC The solubility of KCl is 67 g100 g H2O at 80ordmC and 32 g100 g at 20ordmC Water at 80ordmC is saturated with both at 80ordmC and then cooled to 20ordmC Which precipitates [ANS = KCl]
Consider the following lab data used to find the density of an unknown solid sampleDensity Methanol = 0791 gmlMass Flask + Stopper = 10725 gMass Flask + Stopper + Methanol = 15447 gMass Flask + Stopper + Solid = 13242 gMass Flask + Stopper + Solid+ Methanol = 17612 g
a) What is the volume of the flaskb) What is the density of the solid [ANS = 597 ml 56 gml]
How many grams of water are required to dissolve a mixture made from 18 g of A (solubility = 14 g A100 g water) and 23 g of B (solubility = 25 g B100 g water) assuming the solubilities are independent of each other [ANS = 1286 g water]
What is the density of a liquid which when measured in a flask that holds 5000 mL weighs 43225 g [ANS = 08645 gml]
Calculate the density (gcm3) of a plastic cube that is 500 cm on a side and has a mass of 20375 g [ANS = 163 gcm3]
A saturated solution of compound Q is produced by dissolving 175 g of Q in 500 g of water What is the solubility of Q in grams Q per 1000 g of water [ANS = 350 g]
The density of a certain vegetable oil is 0855 gcm3 When placed in a beaker with water which (water or oil) will settle to the bottom of the beaker [ANS = water]
What is the value of absolute zero (-27315degC) in Fahrenheit [ANS = -45967degF]
Calculate (236 ndash 0899)5445 to the proper number of sig figrsquos [ANS = 796]
Compound A has a solubility of 220g100g water at 27degC and 450g100g at 75degC1 How much water is needed to dissolve 480 g of the compound at 27degC2 A 350 g sample of A is added to 850 g of water at 75degC The solution is then cooled to 27degC How many grams of A will crystallize out[ANS = 218 g H2O 163 g A]
The number of significant figures in the answer to (515 ndash 267) x (3342 ndash 0124) is[ANS = 3 163 x 103]
Which of the following has the largest volume 1 cup = 225 mL [ANS = D]A) 23 cup B) 150 mL C) 378 x 10-2 cup D) 075 cup
An infant ibuprofen suspension contains 100mg50 mL suspension The recommended dose 10 mgkg body weight How many mL of this suspension shouldbe given to an infant weighing 18 lb (Assume 2 significant figures) 1 lb = 4536 g[ANS = 41 ml]
A student made the measurements below in order to obtain the density of an unknown solid In the experiment the volume of the flask was determined by finding the mass of ethanol required to completely fill the empty flaskMass of flask + stopper = 29245 gMass of flask + stopper + ethanol = 48639 gDensity of ethanol = 0789 gmLMass of flask + stopper + solid = 54623 gMass of flask + stopper + solid + ethanol = 71776 g1 What is the volume of the flask2 What is the mass of the unknown3 What is the volume of the unknown4 What is the density of the unknown
An empty flask weighs 65228 g The flask is completely filled with water and the mass of the flask and water is measured at 98002 g If the density of water is 09987 gmL calculate the volume of the flask [ANS = 3282 ml]
Solute A has a solubility of 22 g100 g H2O How many grams of A should be added to 78 g of water to make a saturated solution [ANS = 172 g A]
How many 81 mg tablets can be made from 121 kg aspirin [ANS = 14938 tablets]
A plastic block is 22 cm x 30 cm x 15 cm and has a mass of 124 grams Will the block float in water and why (density of water = 100 gmL) [ANS = c]a) No the density of block is 080 gmL which is greater than the density of waterb) Yes the density of the block is 13 gmL which less than the density of waterc) No the density of block is 13 gmL which is greater than the density of waterd) Yes the density of the block is 080 gmL which is less than the density of watere) none of the above
The solubility of sucrose at 20degC is 204 g100 g of water and at 100degC is 487g100 g A solution at 100degC is prepared by dissolving 245 g of sucrose in 770 g of water The solution is cooled to 20degC How many grams of sugar crystallizes [88 g]
A student made the measurements below in order to obtain the density of an unknown solid In the experiment the volume of the flask is determined by finding the mass of mercury (a dense liquid) required to completely fill the empty flask
Mass of flask + stopper = 495770 gMass of flask + stopper + mercury = 1822263 gDensity of mercury = 135939 gmLMass of flask + stopper + solid = 1312896 gMass of flask + stopper + solid + mercury = 2051045 g
2 What is the mass of unknown solid3 What is the volume of the unknown solid4 What is the density of the unknown solid[ANS = 975800 ml 817126 g 432800 ml 188800 gml]
A solution is 120 of sodium hydroxide by mass and has a density of 1131 gmL What volume of this solution (in mL) contains 350 g of sodium hydroxide
Ch 3A solution is made of 050 mol table salt (NaCl) and 050 mol water What is the mass percent water in the solution [ANS = 236]
What is the mass percent oxygen in (NH4)2CO3 bull10H2O [ANS = 754]
What is the simplest formula of a compound containing only hydrogen and nitrogen which is 126 hydrogen by mass If the substance has a real molar mass of 32 gmol what is its molecular formula [ANS = Simplest is NH2 molecular is N2H4]
For a given reaction the actual yield is 630 g If this represents 660 of the theoretical yield what is
the theoretical yield [ANS = 955 g]
Suppose that instead of carbon-12 fluorine-19 had been chosen as the basis for atomic masses If it
were assigned a mass of exactly 10000 what would the atomic mass of iron be [ANS = 294 gmol]
If the molar mass of a compound is 18016 gmol and its empirical formula is CH2O
what is its molecular formula [ANS = C6H12O6]
How many H atoms in a cup (8 fluid ounces at 284 mLounce) of CH3OH Density = 07918 gmL [ANS = 135 x 1025]
What is the mass of 183 moles H2SO4 [ANS = 17948 g]
The density of ethanol C2H5OH is 0789 gmL 456 mL of ethanol are burned to produce CO2 and water How many grams of water are produced [ANS = 422 g]
C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O
Tartaric acid is the white powdery substance that coats sour candies such as Sour Patch Kids It
contains the elements H C and O Combustion analysis of a 1201 g sample of tartaric acid produced
1408 g CO2 and 432 H2O
Calculate the number of mols and mass of H
Calculate the number of mols and mass of C
Calculate the number of mols and mass of O
What is the simplest formula of tartaric acid
[ANS = 048 g H 048 mol H 384 g C 032 mol C 769 g O 048 mol O C2H3O3]
Consider the following balanced equation How many mols of SO2 needed to produce 165 grams of S
2 H2S(g) + SO2(g) 3 S(s) + 2 H2O(g)
One of the major components of beeswax has the formula C56H118O2 (MM = 824 gmol) Suppose a 1 lb
(435g) candle made of that compound is lit and burns producing carbon dioxide and water It is placed
in a small sealed room that contains 66 mols of oxygen in the air and left to burn Does the candle
burn completely or is the oxygen in the room consumed first
1 Write a balanced chemical equation for the burning of the wax
2 How many mols wax are in the candle
3 How many mols oxygen are required to completely burn the candle
4 Is wax or oxygen left over and how many mols of it remain
Consider the reaction between Si and nitrogen for the formation of Si3N4(s)3Si(s) + 2N2(g) Si3N4(s)15 grams of Si and 25 grams of nitrogen are reacted to form Si3N4(s)1 If 15 g of Si reacts with excess N2 how many moles of Si3N4 are produced2 If 25 g of N2 reacts with excess Si how many moles of Si3N4 are produced3 If 15 g of Si and 25 g of N2 are reacted how many moles of Si3N4 can be formed if the percentage yield is 85 [ANS = 0178 moles 0446 moles 0151 moles]
Consider potassium chlorate KClO3 (MM = 1226 gmol)1 How many oxygen atoms are there in 543 grams of potassium chlorate2 How many grams of potassium are there in 345 grams of potassium chlorate
Suppose fluorine were used as the basis of atomic mass and assigned a mass of 900 What would the atomic mass of copper be when using this basis
What is the simplest formula for the compound C6H12O6
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
(a) Both Rf values would increase and the ions would be further apart at the end
(b) Both Rf values would decrease and the ions would be closer together at the end
(c) The ions would be further separated because the larger Rf value would get bigger and
the smaller Rf value would get smaller
(d) The Rf values would remain constant and the ions would be further apart
(e) The Rf values would remain constant and the ions would be closer together
[ANS = Cu(NO3)2 iron(III) nitrate 074 33 cm d]
The solubility of Li2SO4 is 31 g100 g H2O at 80ordmC and 35 g100 g at 20ordmC The solubility of KCl is 67 g100 g H2O at 80ordmC and 32 g100 g at 20ordmC Water at 80ordmC is saturated with both at 80ordmC and then cooled to 20ordmC Which precipitates [ANS = KCl]
Consider the following lab data used to find the density of an unknown solid sampleDensity Methanol = 0791 gmlMass Flask + Stopper = 10725 gMass Flask + Stopper + Methanol = 15447 gMass Flask + Stopper + Solid = 13242 gMass Flask + Stopper + Solid+ Methanol = 17612 g
a) What is the volume of the flaskb) What is the density of the solid [ANS = 597 ml 56 gml]
How many grams of water are required to dissolve a mixture made from 18 g of A (solubility = 14 g A100 g water) and 23 g of B (solubility = 25 g B100 g water) assuming the solubilities are independent of each other [ANS = 1286 g water]
What is the density of a liquid which when measured in a flask that holds 5000 mL weighs 43225 g [ANS = 08645 gml]
Calculate the density (gcm3) of a plastic cube that is 500 cm on a side and has a mass of 20375 g [ANS = 163 gcm3]
A saturated solution of compound Q is produced by dissolving 175 g of Q in 500 g of water What is the solubility of Q in grams Q per 1000 g of water [ANS = 350 g]
The density of a certain vegetable oil is 0855 gcm3 When placed in a beaker with water which (water or oil) will settle to the bottom of the beaker [ANS = water]
What is the value of absolute zero (-27315degC) in Fahrenheit [ANS = -45967degF]
Calculate (236 ndash 0899)5445 to the proper number of sig figrsquos [ANS = 796]
Compound A has a solubility of 220g100g water at 27degC and 450g100g at 75degC1 How much water is needed to dissolve 480 g of the compound at 27degC2 A 350 g sample of A is added to 850 g of water at 75degC The solution is then cooled to 27degC How many grams of A will crystallize out[ANS = 218 g H2O 163 g A]
The number of significant figures in the answer to (515 ndash 267) x (3342 ndash 0124) is[ANS = 3 163 x 103]
Which of the following has the largest volume 1 cup = 225 mL [ANS = D]A) 23 cup B) 150 mL C) 378 x 10-2 cup D) 075 cup
An infant ibuprofen suspension contains 100mg50 mL suspension The recommended dose 10 mgkg body weight How many mL of this suspension shouldbe given to an infant weighing 18 lb (Assume 2 significant figures) 1 lb = 4536 g[ANS = 41 ml]
A student made the measurements below in order to obtain the density of an unknown solid In the experiment the volume of the flask was determined by finding the mass of ethanol required to completely fill the empty flaskMass of flask + stopper = 29245 gMass of flask + stopper + ethanol = 48639 gDensity of ethanol = 0789 gmLMass of flask + stopper + solid = 54623 gMass of flask + stopper + solid + ethanol = 71776 g1 What is the volume of the flask2 What is the mass of the unknown3 What is the volume of the unknown4 What is the density of the unknown
An empty flask weighs 65228 g The flask is completely filled with water and the mass of the flask and water is measured at 98002 g If the density of water is 09987 gmL calculate the volume of the flask [ANS = 3282 ml]
Solute A has a solubility of 22 g100 g H2O How many grams of A should be added to 78 g of water to make a saturated solution [ANS = 172 g A]
How many 81 mg tablets can be made from 121 kg aspirin [ANS = 14938 tablets]
A plastic block is 22 cm x 30 cm x 15 cm and has a mass of 124 grams Will the block float in water and why (density of water = 100 gmL) [ANS = c]a) No the density of block is 080 gmL which is greater than the density of waterb) Yes the density of the block is 13 gmL which less than the density of waterc) No the density of block is 13 gmL which is greater than the density of waterd) Yes the density of the block is 080 gmL which is less than the density of watere) none of the above
The solubility of sucrose at 20degC is 204 g100 g of water and at 100degC is 487g100 g A solution at 100degC is prepared by dissolving 245 g of sucrose in 770 g of water The solution is cooled to 20degC How many grams of sugar crystallizes [88 g]
A student made the measurements below in order to obtain the density of an unknown solid In the experiment the volume of the flask is determined by finding the mass of mercury (a dense liquid) required to completely fill the empty flask
Mass of flask + stopper = 495770 gMass of flask + stopper + mercury = 1822263 gDensity of mercury = 135939 gmLMass of flask + stopper + solid = 1312896 gMass of flask + stopper + solid + mercury = 2051045 g
2 What is the mass of unknown solid3 What is the volume of the unknown solid4 What is the density of the unknown solid[ANS = 975800 ml 817126 g 432800 ml 188800 gml]
A solution is 120 of sodium hydroxide by mass and has a density of 1131 gmL What volume of this solution (in mL) contains 350 g of sodium hydroxide
Ch 3A solution is made of 050 mol table salt (NaCl) and 050 mol water What is the mass percent water in the solution [ANS = 236]
What is the mass percent oxygen in (NH4)2CO3 bull10H2O [ANS = 754]
What is the simplest formula of a compound containing only hydrogen and nitrogen which is 126 hydrogen by mass If the substance has a real molar mass of 32 gmol what is its molecular formula [ANS = Simplest is NH2 molecular is N2H4]
For a given reaction the actual yield is 630 g If this represents 660 of the theoretical yield what is
the theoretical yield [ANS = 955 g]
Suppose that instead of carbon-12 fluorine-19 had been chosen as the basis for atomic masses If it
were assigned a mass of exactly 10000 what would the atomic mass of iron be [ANS = 294 gmol]
If the molar mass of a compound is 18016 gmol and its empirical formula is CH2O
what is its molecular formula [ANS = C6H12O6]
How many H atoms in a cup (8 fluid ounces at 284 mLounce) of CH3OH Density = 07918 gmL [ANS = 135 x 1025]
What is the mass of 183 moles H2SO4 [ANS = 17948 g]
The density of ethanol C2H5OH is 0789 gmL 456 mL of ethanol are burned to produce CO2 and water How many grams of water are produced [ANS = 422 g]
C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O
Tartaric acid is the white powdery substance that coats sour candies such as Sour Patch Kids It
contains the elements H C and O Combustion analysis of a 1201 g sample of tartaric acid produced
1408 g CO2 and 432 H2O
Calculate the number of mols and mass of H
Calculate the number of mols and mass of C
Calculate the number of mols and mass of O
What is the simplest formula of tartaric acid
[ANS = 048 g H 048 mol H 384 g C 032 mol C 769 g O 048 mol O C2H3O3]
Consider the following balanced equation How many mols of SO2 needed to produce 165 grams of S
2 H2S(g) + SO2(g) 3 S(s) + 2 H2O(g)
One of the major components of beeswax has the formula C56H118O2 (MM = 824 gmol) Suppose a 1 lb
(435g) candle made of that compound is lit and burns producing carbon dioxide and water It is placed
in a small sealed room that contains 66 mols of oxygen in the air and left to burn Does the candle
burn completely or is the oxygen in the room consumed first
1 Write a balanced chemical equation for the burning of the wax
2 How many mols wax are in the candle
3 How many mols oxygen are required to completely burn the candle
4 Is wax or oxygen left over and how many mols of it remain
Consider the reaction between Si and nitrogen for the formation of Si3N4(s)3Si(s) + 2N2(g) Si3N4(s)15 grams of Si and 25 grams of nitrogen are reacted to form Si3N4(s)1 If 15 g of Si reacts with excess N2 how many moles of Si3N4 are produced2 If 25 g of N2 reacts with excess Si how many moles of Si3N4 are produced3 If 15 g of Si and 25 g of N2 are reacted how many moles of Si3N4 can be formed if the percentage yield is 85 [ANS = 0178 moles 0446 moles 0151 moles]
Consider potassium chlorate KClO3 (MM = 1226 gmol)1 How many oxygen atoms are there in 543 grams of potassium chlorate2 How many grams of potassium are there in 345 grams of potassium chlorate
Suppose fluorine were used as the basis of atomic mass and assigned a mass of 900 What would the atomic mass of copper be when using this basis
What is the simplest formula for the compound C6H12O6
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
What is the value of absolute zero (-27315degC) in Fahrenheit [ANS = -45967degF]
Calculate (236 ndash 0899)5445 to the proper number of sig figrsquos [ANS = 796]
Compound A has a solubility of 220g100g water at 27degC and 450g100g at 75degC1 How much water is needed to dissolve 480 g of the compound at 27degC2 A 350 g sample of A is added to 850 g of water at 75degC The solution is then cooled to 27degC How many grams of A will crystallize out[ANS = 218 g H2O 163 g A]
The number of significant figures in the answer to (515 ndash 267) x (3342 ndash 0124) is[ANS = 3 163 x 103]
Which of the following has the largest volume 1 cup = 225 mL [ANS = D]A) 23 cup B) 150 mL C) 378 x 10-2 cup D) 075 cup
An infant ibuprofen suspension contains 100mg50 mL suspension The recommended dose 10 mgkg body weight How many mL of this suspension shouldbe given to an infant weighing 18 lb (Assume 2 significant figures) 1 lb = 4536 g[ANS = 41 ml]
A student made the measurements below in order to obtain the density of an unknown solid In the experiment the volume of the flask was determined by finding the mass of ethanol required to completely fill the empty flaskMass of flask + stopper = 29245 gMass of flask + stopper + ethanol = 48639 gDensity of ethanol = 0789 gmLMass of flask + stopper + solid = 54623 gMass of flask + stopper + solid + ethanol = 71776 g1 What is the volume of the flask2 What is the mass of the unknown3 What is the volume of the unknown4 What is the density of the unknown
An empty flask weighs 65228 g The flask is completely filled with water and the mass of the flask and water is measured at 98002 g If the density of water is 09987 gmL calculate the volume of the flask [ANS = 3282 ml]
Solute A has a solubility of 22 g100 g H2O How many grams of A should be added to 78 g of water to make a saturated solution [ANS = 172 g A]
How many 81 mg tablets can be made from 121 kg aspirin [ANS = 14938 tablets]
A plastic block is 22 cm x 30 cm x 15 cm and has a mass of 124 grams Will the block float in water and why (density of water = 100 gmL) [ANS = c]a) No the density of block is 080 gmL which is greater than the density of waterb) Yes the density of the block is 13 gmL which less than the density of waterc) No the density of block is 13 gmL which is greater than the density of waterd) Yes the density of the block is 080 gmL which is less than the density of watere) none of the above
The solubility of sucrose at 20degC is 204 g100 g of water and at 100degC is 487g100 g A solution at 100degC is prepared by dissolving 245 g of sucrose in 770 g of water The solution is cooled to 20degC How many grams of sugar crystallizes [88 g]
A student made the measurements below in order to obtain the density of an unknown solid In the experiment the volume of the flask is determined by finding the mass of mercury (a dense liquid) required to completely fill the empty flask
Mass of flask + stopper = 495770 gMass of flask + stopper + mercury = 1822263 gDensity of mercury = 135939 gmLMass of flask + stopper + solid = 1312896 gMass of flask + stopper + solid + mercury = 2051045 g
2 What is the mass of unknown solid3 What is the volume of the unknown solid4 What is the density of the unknown solid[ANS = 975800 ml 817126 g 432800 ml 188800 gml]
A solution is 120 of sodium hydroxide by mass and has a density of 1131 gmL What volume of this solution (in mL) contains 350 g of sodium hydroxide
Ch 3A solution is made of 050 mol table salt (NaCl) and 050 mol water What is the mass percent water in the solution [ANS = 236]
What is the mass percent oxygen in (NH4)2CO3 bull10H2O [ANS = 754]
What is the simplest formula of a compound containing only hydrogen and nitrogen which is 126 hydrogen by mass If the substance has a real molar mass of 32 gmol what is its molecular formula [ANS = Simplest is NH2 molecular is N2H4]
For a given reaction the actual yield is 630 g If this represents 660 of the theoretical yield what is
the theoretical yield [ANS = 955 g]
Suppose that instead of carbon-12 fluorine-19 had been chosen as the basis for atomic masses If it
were assigned a mass of exactly 10000 what would the atomic mass of iron be [ANS = 294 gmol]
If the molar mass of a compound is 18016 gmol and its empirical formula is CH2O
what is its molecular formula [ANS = C6H12O6]
How many H atoms in a cup (8 fluid ounces at 284 mLounce) of CH3OH Density = 07918 gmL [ANS = 135 x 1025]
What is the mass of 183 moles H2SO4 [ANS = 17948 g]
The density of ethanol C2H5OH is 0789 gmL 456 mL of ethanol are burned to produce CO2 and water How many grams of water are produced [ANS = 422 g]
C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O
Tartaric acid is the white powdery substance that coats sour candies such as Sour Patch Kids It
contains the elements H C and O Combustion analysis of a 1201 g sample of tartaric acid produced
1408 g CO2 and 432 H2O
Calculate the number of mols and mass of H
Calculate the number of mols and mass of C
Calculate the number of mols and mass of O
What is the simplest formula of tartaric acid
[ANS = 048 g H 048 mol H 384 g C 032 mol C 769 g O 048 mol O C2H3O3]
Consider the following balanced equation How many mols of SO2 needed to produce 165 grams of S
2 H2S(g) + SO2(g) 3 S(s) + 2 H2O(g)
One of the major components of beeswax has the formula C56H118O2 (MM = 824 gmol) Suppose a 1 lb
(435g) candle made of that compound is lit and burns producing carbon dioxide and water It is placed
in a small sealed room that contains 66 mols of oxygen in the air and left to burn Does the candle
burn completely or is the oxygen in the room consumed first
1 Write a balanced chemical equation for the burning of the wax
2 How many mols wax are in the candle
3 How many mols oxygen are required to completely burn the candle
4 Is wax or oxygen left over and how many mols of it remain
Consider the reaction between Si and nitrogen for the formation of Si3N4(s)3Si(s) + 2N2(g) Si3N4(s)15 grams of Si and 25 grams of nitrogen are reacted to form Si3N4(s)1 If 15 g of Si reacts with excess N2 how many moles of Si3N4 are produced2 If 25 g of N2 reacts with excess Si how many moles of Si3N4 are produced3 If 15 g of Si and 25 g of N2 are reacted how many moles of Si3N4 can be formed if the percentage yield is 85 [ANS = 0178 moles 0446 moles 0151 moles]
Consider potassium chlorate KClO3 (MM = 1226 gmol)1 How many oxygen atoms are there in 543 grams of potassium chlorate2 How many grams of potassium are there in 345 grams of potassium chlorate
Suppose fluorine were used as the basis of atomic mass and assigned a mass of 900 What would the atomic mass of copper be when using this basis
What is the simplest formula for the compound C6H12O6
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
An empty flask weighs 65228 g The flask is completely filled with water and the mass of the flask and water is measured at 98002 g If the density of water is 09987 gmL calculate the volume of the flask [ANS = 3282 ml]
Solute A has a solubility of 22 g100 g H2O How many grams of A should be added to 78 g of water to make a saturated solution [ANS = 172 g A]
How many 81 mg tablets can be made from 121 kg aspirin [ANS = 14938 tablets]
A plastic block is 22 cm x 30 cm x 15 cm and has a mass of 124 grams Will the block float in water and why (density of water = 100 gmL) [ANS = c]a) No the density of block is 080 gmL which is greater than the density of waterb) Yes the density of the block is 13 gmL which less than the density of waterc) No the density of block is 13 gmL which is greater than the density of waterd) Yes the density of the block is 080 gmL which is less than the density of watere) none of the above
The solubility of sucrose at 20degC is 204 g100 g of water and at 100degC is 487g100 g A solution at 100degC is prepared by dissolving 245 g of sucrose in 770 g of water The solution is cooled to 20degC How many grams of sugar crystallizes [88 g]
A student made the measurements below in order to obtain the density of an unknown solid In the experiment the volume of the flask is determined by finding the mass of mercury (a dense liquid) required to completely fill the empty flask
Mass of flask + stopper = 495770 gMass of flask + stopper + mercury = 1822263 gDensity of mercury = 135939 gmLMass of flask + stopper + solid = 1312896 gMass of flask + stopper + solid + mercury = 2051045 g
2 What is the mass of unknown solid3 What is the volume of the unknown solid4 What is the density of the unknown solid[ANS = 975800 ml 817126 g 432800 ml 188800 gml]
A solution is 120 of sodium hydroxide by mass and has a density of 1131 gmL What volume of this solution (in mL) contains 350 g of sodium hydroxide
Ch 3A solution is made of 050 mol table salt (NaCl) and 050 mol water What is the mass percent water in the solution [ANS = 236]
What is the mass percent oxygen in (NH4)2CO3 bull10H2O [ANS = 754]
What is the simplest formula of a compound containing only hydrogen and nitrogen which is 126 hydrogen by mass If the substance has a real molar mass of 32 gmol what is its molecular formula [ANS = Simplest is NH2 molecular is N2H4]
For a given reaction the actual yield is 630 g If this represents 660 of the theoretical yield what is
the theoretical yield [ANS = 955 g]
Suppose that instead of carbon-12 fluorine-19 had been chosen as the basis for atomic masses If it
were assigned a mass of exactly 10000 what would the atomic mass of iron be [ANS = 294 gmol]
If the molar mass of a compound is 18016 gmol and its empirical formula is CH2O
what is its molecular formula [ANS = C6H12O6]
How many H atoms in a cup (8 fluid ounces at 284 mLounce) of CH3OH Density = 07918 gmL [ANS = 135 x 1025]
What is the mass of 183 moles H2SO4 [ANS = 17948 g]
The density of ethanol C2H5OH is 0789 gmL 456 mL of ethanol are burned to produce CO2 and water How many grams of water are produced [ANS = 422 g]
C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O
Tartaric acid is the white powdery substance that coats sour candies such as Sour Patch Kids It
contains the elements H C and O Combustion analysis of a 1201 g sample of tartaric acid produced
1408 g CO2 and 432 H2O
Calculate the number of mols and mass of H
Calculate the number of mols and mass of C
Calculate the number of mols and mass of O
What is the simplest formula of tartaric acid
[ANS = 048 g H 048 mol H 384 g C 032 mol C 769 g O 048 mol O C2H3O3]
Consider the following balanced equation How many mols of SO2 needed to produce 165 grams of S
2 H2S(g) + SO2(g) 3 S(s) + 2 H2O(g)
One of the major components of beeswax has the formula C56H118O2 (MM = 824 gmol) Suppose a 1 lb
(435g) candle made of that compound is lit and burns producing carbon dioxide and water It is placed
in a small sealed room that contains 66 mols of oxygen in the air and left to burn Does the candle
burn completely or is the oxygen in the room consumed first
1 Write a balanced chemical equation for the burning of the wax
2 How many mols wax are in the candle
3 How many mols oxygen are required to completely burn the candle
4 Is wax or oxygen left over and how many mols of it remain
Consider the reaction between Si and nitrogen for the formation of Si3N4(s)3Si(s) + 2N2(g) Si3N4(s)15 grams of Si and 25 grams of nitrogen are reacted to form Si3N4(s)1 If 15 g of Si reacts with excess N2 how many moles of Si3N4 are produced2 If 25 g of N2 reacts with excess Si how many moles of Si3N4 are produced3 If 15 g of Si and 25 g of N2 are reacted how many moles of Si3N4 can be formed if the percentage yield is 85 [ANS = 0178 moles 0446 moles 0151 moles]
Consider potassium chlorate KClO3 (MM = 1226 gmol)1 How many oxygen atoms are there in 543 grams of potassium chlorate2 How many grams of potassium are there in 345 grams of potassium chlorate
Suppose fluorine were used as the basis of atomic mass and assigned a mass of 900 What would the atomic mass of copper be when using this basis
What is the simplest formula for the compound C6H12O6
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
2 What is the mass of unknown solid3 What is the volume of the unknown solid4 What is the density of the unknown solid[ANS = 975800 ml 817126 g 432800 ml 188800 gml]
A solution is 120 of sodium hydroxide by mass and has a density of 1131 gmL What volume of this solution (in mL) contains 350 g of sodium hydroxide
Ch 3A solution is made of 050 mol table salt (NaCl) and 050 mol water What is the mass percent water in the solution [ANS = 236]
What is the mass percent oxygen in (NH4)2CO3 bull10H2O [ANS = 754]
What is the simplest formula of a compound containing only hydrogen and nitrogen which is 126 hydrogen by mass If the substance has a real molar mass of 32 gmol what is its molecular formula [ANS = Simplest is NH2 molecular is N2H4]
For a given reaction the actual yield is 630 g If this represents 660 of the theoretical yield what is
the theoretical yield [ANS = 955 g]
Suppose that instead of carbon-12 fluorine-19 had been chosen as the basis for atomic masses If it
were assigned a mass of exactly 10000 what would the atomic mass of iron be [ANS = 294 gmol]
If the molar mass of a compound is 18016 gmol and its empirical formula is CH2O
what is its molecular formula [ANS = C6H12O6]
How many H atoms in a cup (8 fluid ounces at 284 mLounce) of CH3OH Density = 07918 gmL [ANS = 135 x 1025]
What is the mass of 183 moles H2SO4 [ANS = 17948 g]
The density of ethanol C2H5OH is 0789 gmL 456 mL of ethanol are burned to produce CO2 and water How many grams of water are produced [ANS = 422 g]
C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O
Tartaric acid is the white powdery substance that coats sour candies such as Sour Patch Kids It
contains the elements H C and O Combustion analysis of a 1201 g sample of tartaric acid produced
1408 g CO2 and 432 H2O
Calculate the number of mols and mass of H
Calculate the number of mols and mass of C
Calculate the number of mols and mass of O
What is the simplest formula of tartaric acid
[ANS = 048 g H 048 mol H 384 g C 032 mol C 769 g O 048 mol O C2H3O3]
Consider the following balanced equation How many mols of SO2 needed to produce 165 grams of S
2 H2S(g) + SO2(g) 3 S(s) + 2 H2O(g)
One of the major components of beeswax has the formula C56H118O2 (MM = 824 gmol) Suppose a 1 lb
(435g) candle made of that compound is lit and burns producing carbon dioxide and water It is placed
in a small sealed room that contains 66 mols of oxygen in the air and left to burn Does the candle
burn completely or is the oxygen in the room consumed first
1 Write a balanced chemical equation for the burning of the wax
2 How many mols wax are in the candle
3 How many mols oxygen are required to completely burn the candle
4 Is wax or oxygen left over and how many mols of it remain
Consider the reaction between Si and nitrogen for the formation of Si3N4(s)3Si(s) + 2N2(g) Si3N4(s)15 grams of Si and 25 grams of nitrogen are reacted to form Si3N4(s)1 If 15 g of Si reacts with excess N2 how many moles of Si3N4 are produced2 If 25 g of N2 reacts with excess Si how many moles of Si3N4 are produced3 If 15 g of Si and 25 g of N2 are reacted how many moles of Si3N4 can be formed if the percentage yield is 85 [ANS = 0178 moles 0446 moles 0151 moles]
Consider potassium chlorate KClO3 (MM = 1226 gmol)1 How many oxygen atoms are there in 543 grams of potassium chlorate2 How many grams of potassium are there in 345 grams of potassium chlorate
Suppose fluorine were used as the basis of atomic mass and assigned a mass of 900 What would the atomic mass of copper be when using this basis
What is the simplest formula for the compound C6H12O6
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Ch 3A solution is made of 050 mol table salt (NaCl) and 050 mol water What is the mass percent water in the solution [ANS = 236]
What is the mass percent oxygen in (NH4)2CO3 bull10H2O [ANS = 754]
What is the simplest formula of a compound containing only hydrogen and nitrogen which is 126 hydrogen by mass If the substance has a real molar mass of 32 gmol what is its molecular formula [ANS = Simplest is NH2 molecular is N2H4]
For a given reaction the actual yield is 630 g If this represents 660 of the theoretical yield what is
the theoretical yield [ANS = 955 g]
Suppose that instead of carbon-12 fluorine-19 had been chosen as the basis for atomic masses If it
were assigned a mass of exactly 10000 what would the atomic mass of iron be [ANS = 294 gmol]
If the molar mass of a compound is 18016 gmol and its empirical formula is CH2O
what is its molecular formula [ANS = C6H12O6]
How many H atoms in a cup (8 fluid ounces at 284 mLounce) of CH3OH Density = 07918 gmL [ANS = 135 x 1025]
What is the mass of 183 moles H2SO4 [ANS = 17948 g]
The density of ethanol C2H5OH is 0789 gmL 456 mL of ethanol are burned to produce CO2 and water How many grams of water are produced [ANS = 422 g]
C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O
Tartaric acid is the white powdery substance that coats sour candies such as Sour Patch Kids It
contains the elements H C and O Combustion analysis of a 1201 g sample of tartaric acid produced
1408 g CO2 and 432 H2O
Calculate the number of mols and mass of H
Calculate the number of mols and mass of C
Calculate the number of mols and mass of O
What is the simplest formula of tartaric acid
[ANS = 048 g H 048 mol H 384 g C 032 mol C 769 g O 048 mol O C2H3O3]
Consider the following balanced equation How many mols of SO2 needed to produce 165 grams of S
2 H2S(g) + SO2(g) 3 S(s) + 2 H2O(g)
One of the major components of beeswax has the formula C56H118O2 (MM = 824 gmol) Suppose a 1 lb
(435g) candle made of that compound is lit and burns producing carbon dioxide and water It is placed
in a small sealed room that contains 66 mols of oxygen in the air and left to burn Does the candle
burn completely or is the oxygen in the room consumed first
1 Write a balanced chemical equation for the burning of the wax
2 How many mols wax are in the candle
3 How many mols oxygen are required to completely burn the candle
4 Is wax or oxygen left over and how many mols of it remain
Consider the reaction between Si and nitrogen for the formation of Si3N4(s)3Si(s) + 2N2(g) Si3N4(s)15 grams of Si and 25 grams of nitrogen are reacted to form Si3N4(s)1 If 15 g of Si reacts with excess N2 how many moles of Si3N4 are produced2 If 25 g of N2 reacts with excess Si how many moles of Si3N4 are produced3 If 15 g of Si and 25 g of N2 are reacted how many moles of Si3N4 can be formed if the percentage yield is 85 [ANS = 0178 moles 0446 moles 0151 moles]
Consider potassium chlorate KClO3 (MM = 1226 gmol)1 How many oxygen atoms are there in 543 grams of potassium chlorate2 How many grams of potassium are there in 345 grams of potassium chlorate
Suppose fluorine were used as the basis of atomic mass and assigned a mass of 900 What would the atomic mass of copper be when using this basis
What is the simplest formula for the compound C6H12O6
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
The density of ethanol C2H5OH is 0789 gmL 456 mL of ethanol are burned to produce CO2 and water How many grams of water are produced [ANS = 422 g]
C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O
Tartaric acid is the white powdery substance that coats sour candies such as Sour Patch Kids It
contains the elements H C and O Combustion analysis of a 1201 g sample of tartaric acid produced
1408 g CO2 and 432 H2O
Calculate the number of mols and mass of H
Calculate the number of mols and mass of C
Calculate the number of mols and mass of O
What is the simplest formula of tartaric acid
[ANS = 048 g H 048 mol H 384 g C 032 mol C 769 g O 048 mol O C2H3O3]
Consider the following balanced equation How many mols of SO2 needed to produce 165 grams of S
2 H2S(g) + SO2(g) 3 S(s) + 2 H2O(g)
One of the major components of beeswax has the formula C56H118O2 (MM = 824 gmol) Suppose a 1 lb
(435g) candle made of that compound is lit and burns producing carbon dioxide and water It is placed
in a small sealed room that contains 66 mols of oxygen in the air and left to burn Does the candle
burn completely or is the oxygen in the room consumed first
1 Write a balanced chemical equation for the burning of the wax
2 How many mols wax are in the candle
3 How many mols oxygen are required to completely burn the candle
4 Is wax or oxygen left over and how many mols of it remain
Consider the reaction between Si and nitrogen for the formation of Si3N4(s)3Si(s) + 2N2(g) Si3N4(s)15 grams of Si and 25 grams of nitrogen are reacted to form Si3N4(s)1 If 15 g of Si reacts with excess N2 how many moles of Si3N4 are produced2 If 25 g of N2 reacts with excess Si how many moles of Si3N4 are produced3 If 15 g of Si and 25 g of N2 are reacted how many moles of Si3N4 can be formed if the percentage yield is 85 [ANS = 0178 moles 0446 moles 0151 moles]
Consider potassium chlorate KClO3 (MM = 1226 gmol)1 How many oxygen atoms are there in 543 grams of potassium chlorate2 How many grams of potassium are there in 345 grams of potassium chlorate
Suppose fluorine were used as the basis of atomic mass and assigned a mass of 900 What would the atomic mass of copper be when using this basis
What is the simplest formula for the compound C6H12O6
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Consider potassium chlorate KClO3 (MM = 1226 gmol)1 How many oxygen atoms are there in 543 grams of potassium chlorate2 How many grams of potassium are there in 345 grams of potassium chlorate
Suppose fluorine were used as the basis of atomic mass and assigned a mass of 900 What would the atomic mass of copper be when using this basis
What is the simplest formula for the compound C6H12O6
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Consider the unbalanced reaction__CH3NH2(g) + __O2(g) rarr __N2(g) + __H2O(g) + __CO2(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients) [16 balanced rxn coefficients are 492104]]
If the actual yield of a reaction is 682 and 155 g of product forms what is the theoretical yield [227 g]
The compound C6H12O2N has half as many grams of carbon as hydrogen (Y or N) [No has 72 g C and 12 g H it has half as many moles of C as H]
What is the mass in grams of 652 x 1021 molecules of aspirin C9H8O4 [195 g]
What is the mass percent of O in a compound with a formula C7H5(NO2)3(MM = 22714 gmol)
Lead (II) oxide reacts with ammonia as follows3PbO(s) + 2NH3(g) 3Pb(s) + N2(g) + 3H2O(l)1 How many grams of PbO are consumed in the reaction of 816 g PbO(MM of PbO is 2232 gmol)2 If 0312 g of NH3 is available to react with 816 g PbO how many grams ofPb are produced3 If the actual yield is 495 g Pb what is the percent yield[ANS = 0415 g 569 g 87]
Benzocaine is a compound containing carbon oxygen hydrogen andnitrogen When a sample of benzocaine weighing 354 g is burned in excessoxygen 849 g of CO2 and 214 g of H2O are formed In a separate experiment thepercentage of N is determined to be 8468 1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 How many grams of oxygen are in the sample5 What is the simplest formula[232 g C 0239 g H 0300 g N 0681 g Ox C9H11O2N)
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
An oxide of a metal Q has the formula QO4 The oxide reacts with excess H2 to yield the free metal and H2O according to the following balanced reactionQO4(s) + 4H2(g) Q(s) + 4H2O(l)1 A 1129 g sample of QO4 yields 3198 g of H2O How many moles H2O produced2 How many moles of QO4 are consumed3 What is the molar mass of QO44 What is the atomic mass of Q5 What element is Q(01775 004437 2545 1905 Os)
In determining the simplest formula of vanadium oxide 43498 g of vanadium are placed in a crucible with 4010 grams of oxygen which is in excessWhen the reaction is complete the product has a mass of 77656 grams1 How many moles of vanadium are there in the product2 How many grams of oxygen are there in the product3 How many moles of oxygen are there in the product4 Calculate the excess amount (in grams) of oxygen used in this experiment5 What is the simplest formula of vanadium oxide
65 g of a compound containing C H and O is burned with excess oxygen 16628 g CO2 and 6804 g of H2O are formed What is the simplest formula of the compound[C5H10O]
035 g of a C H N containing compound is burned in excess oxygen 06695 g CO2 and 05478 g H2O are formed What is the simplest formula of the compound[C2H8N]
A compound has a ratio of CrO of 108 by mass What is the simplest formula of the compound [ANS = CrO3]
0150 g of a compound containing C H N Cl and O is run through a series of reactions to isolate each element The C ends up in 0138 g CO2 the H in 00566 g H2O the N in 0017 g NH3 and the Cl in 03014 g AgCl The O is never specifically isolated What is the simplest formula of the compound [Answer C3H6NCl2O]
A molecular compound contains 923 carbon and 77 H by weight If 0125 mol of the compound weighs 325 g what is its molecular formula
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
A mixture containing 100 mole of NH3 and 180 mole of nitrogen oxide according to4NH3(g) + 6NO(g) 5N2(g) + 6 H2O (ℓ)a What is the limiting reactantb How many moles of N2 are producedc How many moles of the reactant in excess remaind If 0800 moles of H2O are actually produced what is the yield of the reactione Write the name for NH3
Cyanogen gas C2N2 has been found in the gases of outer space It can react with fluorine to form carbon tetrafluoride and nitrogen trifluorideC2N2(s) + 7F2(g) 2CF4(g) + 2NF3(s)1 What is the molar mass of cyanogen2 How many moles are there in 3200 g of fluorine gas F23 How many atoms are there in 500 g of carbon tetrafluoride4 How many grams of fluorine needed to produce 4981 mol of nitrogen trifluoride5 A student is asked to make 1000 g of the carbon tetrafluoride He is told that thereaction had a 80 yield How many grams of cyanogen will he need to react withan excess of fluorine gas
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
If S-32 were assigned as the standard for expressing relative atomicmasses and assigned an atomic mass of 1000 amu What would theatomic mass of cobalt be using this basis
What is the simplest formula for the compound C12H22O11
Consider the unbalanced reaction__NaCℓ(g) + __SO2(g) + __H2O(g) + __O2(g) rarr __N2SO4(s) + __HCℓ(g)Once balanced what is the sum of coefficients for the products (usesmallest whole number coefficients)
If the actual yield of a reaction is 882 and 255 g of product forms what is the theoretical yield
The compound C6H12O2N has half as many grams of hydrogen as carbon (Y or N)
Copper has two naturally occurring isotopes Cu-63 has an atomic mass of 629296 and an abundance of 6917 What is the atomic mass of the second isotope
Calculate the average mass of a sodium atom in grams
Citric acid has the formula C6H8O7 (MM = 19212 gmol) How many hydrogenatoms are there in 50 g of citric acid
What is the mass percent of C in a compound with a formula (C5H5)2Fe
0150 g of a C H N Cl and Oxygen compound is burned in excess oxygen and found to produce 0138 g CO2 and 00566 g H2O The nitrogen is isolated as NH3 and 0017 g NH3 is obtained The Cl is isolated as AgCl and 03014 g AgCl is obtained What is the simplest formula of the C H N Cl and Oxygen compound [ANS = C2H4NCl3O]
Hexamethylenediamine (MW = 1162 gmol) a compound made up of
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
carbon hydrogen and nitrogen atoms is used in the production of nylon When6315 g of hexamethylenediamine is burned in oxygen 1436 g of carbon dioxideand 7832 g of water are obtained1 How many grams of carbon are in the sample2 How many grams of hydrogen are in the sample3 How many grams of nitrogen are in the sample4 What is the simplest formula for hexamethylenediamine
A strip of zinc metal is placed in an aqueous solution containing AgNO3causing the following reaction to occurZn(s) + 2AgNO3(aq) rarr 2Ag(s) + Zn(NO3)2(aq)1 If 200 grams of zinc metal reacts with an excess of AgNO3 how many moles ofsilver can be produced2 If 250 grams of silver nitrate reacts with an excess of zinc metal how many moles of silver can be produced3 If 200 grams of zinc metal and 250 grams of silver nitrate react how many grams of silver can theoretically be produced4 How many moles of the excess reactant remain after the complete reaction5 If the actual yield of Ag is 121 grams what is the percent yield for the reaction
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
The concentration of NH4+ ions in a solution made from 030 mol (NH4)2CO3
diluted to a total volume of 10 L is (GT LT EQ) 030 M
Complete the following half reactionCH3OH(aq) + 2OH-(aq) CH2O(aq) + ___ + 2H2O
What is the oxidation number of iron in Fe3O4
How many moles Na2CO3 are needed to react completely with 0450 L 0100 M HCl
You have two bottles with clear colorless aqueous solutions marked A and B One contains NaCl and the other contains Na3PO4 To determine which is which you take a small sample from bottle B mix it with a small sample of Ca(NO3)2 (aq) and a precipitate forms Bottle B contains
Write the capital letter for the equation above that represents(a) a precipitation reaction(b) reaction of a weak base with water (c) net ionic equation for a strong acid and strong base reaction(d) reaction between a weak base and a strong acid(e) reaction between a weak acid and strong base
2 Consider separate solrsquons of soluble compounds Na3PO4 FeCl3 (NH4)2CO3 Write formulas for all insoluble compounds that can be formed by mixing these solrsquons
A 250 L solution of K2CrO4 is prepared by dissolving 875 g K2CrO4 in water(a) What is the molarity of the solution(b) What is the molarity of the potassium ions in the solution above(c) Potassium chromate K2CrO4 was used as an indicator for the end point of thetitration of an unknown chloride with silver nitrate solution Silver chromateAg2CrO4 is an insoluble solid Write a net ionic equation for reaction of silver ionand chromate ion to form solid silver chromate Indicate states(d) Suppose that 040 mL of 050 M K2CrO4 solution was used as the indicator What
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
volume of 015 M silver nitrate solution is needed to react completely with thisamount of K2CrO4 indicator
6 g of Al (s) reacts with excess hydrochloric acid How many liters of wet gas will be produced a total pressure of 1 atm at 298 K (vapor pressure of water at 298 K is 2376 mm Hg) [ANS = 8425 L (is 03336 moles H2)
What volume of 03 M NH3 will completely neutralize 25 ml of 01 M H2SO4[ANS ndash 1667 ml]
What mass of precipitate will form if 65 ml of 02 M Ba(OH)2 solution reacts with excess Co(NO3)3 solution [ANS = 0953 g]
For the balanced redox reaction run in acid solution12H+(aq) + 2IO3
-(aq) + 10I-(aq) 6I2(aq) + 6H2O82 ml of 043M KI solution is mixed with 55 mL of 097 M potassium iodate solution1 If 82 mL of 095 M KI reacts with excess KIO3 how many moles I2 produced2 If 55 mL of 042 M KIO3 reacts with excess KI how many moles I2 produced3 If 82 mL of 095 M KI and 55 mL of 042 M KIO3 react how many moles I2 can be produced4 What is the concentration of iodine in the resultant solution (Volumes additive)
A sample of a chloride salt weighing 4846 mg is titrated with AgNO3 using K2CrO4
as indicator To reach the end point a 523 mL of 01475 M of AgNO3 solution isrequired How many moles of chloride were in that sample
A sample of weak acid HB is titrated with 4321 mL of 01122 M KOH for neutralization to a phenolphthalein end point How many moles HB in the sample
A 0432 g sample of a weak base is titrated to an appropriate end point with 2553 mL of 01555 M HNO31 How many moles H+ were used2 How many moles base were in the sample3 What is the molar mass of the weak base
The iron content of a sample can be determined by titration with potassium permanganate in acid The oxidation and reduction half reactions which are involved in this titration are given as follows8H+ (aq) + MnO4 - (aq) + 5e- Mn2+ (aq) + 4H2OFe2+ (aq) Fe3+ (aq) + e-1 How many moles of Fe2+ can be oxidized to Fe3+ by 175 x 10-2 mol of MnO4-2 What is the mass of iron in the sample
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Answer the questions below using LT GT EQ or MI (for more information required)2 The oxidation number of Cℓ in CℓO4- is the oxidation number of Cℓ in CℓO3- is3 The volume of 0100 M NaOH needed to react completely with 250 mL of0100 M H2SO4 is __ than 250 mL5 The concentration of OH- in a solution of 015 M NH3 (aq) is __ 015 M2 The oxidation number of O in Na2O2 is __ the oxidation number of O in O24 The number of s electrons in Fe3+ is __ 85 The concentration of H+ in one liter of 015 M HNO2 is ___ 015
When aqueous solutions of barium hydroxide and iron (III) nitrate aremixed a red precipitate formsFe3+ (aq) + 3OH- (aq) Fe(OH)3 (s)What is the mass of the precipitate when 5000 mL of 0200 M Ba(OH)2 is mixed with an excess of 0125 M Fe(NO3)3
Laundry bleach is a solution of sodium hypochlorite (NaClO) To determine the hypochlorite (ClO-) content of bleach (which is responsible for its bleaching action) sulfide ion is added in basic solution The balanced equation for the reaction is ClO-(aq) + S2-(aq) + H2O Cl-(aq) + S(s) + 2OH-(aq) The chloride ion resulting from the reduction of NaClO is precipitated as AgCl When 500 mL of laundry bleach (d = 102 gmL) is treated as described above 495 g of AgCl is obtained1 How many moles of AgCl precipitated2 How many moles of OCl- ions are present3 What is the mass percent of NaClO in the bleach sample
When solutions of K2CO3 (aq) and Mg(NO3)2 are mixed a precipitate of _____ forms
Write the balanced net ionic equation for the following reaction An aqueous solution of magnesium chloride is added to an aqueous solution of silver nitrate What are the spectator ions
Calculate the concentration of a solution made by dissolving 100 g ofsodium chloride NaCl in 7500mL of solution
A 5000 mL of 0200 M iron (III) nitrate is mixed with 0400 M calcium hydroxide What is the minimum volume of calcium hydroxide required to completely precipitate iron (III) hydroxide
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Calculate the concentration of perchlorate ions in solution after 247 mL of 172 M HClO4 is added to 192 mL of 179 M KOH and the resulting solution is diluted to 5000 mL with water
If 50 ml of 01 M Ca(NO3)2 is mixed with 62 ml 005 M Na3PO4How many grams precipitate will form [ANS = 048 g]What will final concentration of excess reactant ion be [ANS = 00031 M]
Calculate the concentration of HCl if 25 0 mL of the acid solution is titrated with 196 mL of 210 M Ca(OH)2 to produce CaCl2 and water
Consider the following reaction2K(s) + 2H2O _ 2KOH(aq) + H2(g)1 The oxidizing agent is ________2 The base is ______3 The number of electrons involved in the oxidation half reaction is _____ (use smallest whole number coefficients)4 Which element is reduced _____
Consider the following unbalanced oxidation-reduction reaction in acid solution Answer the following questionsH3PO2(aq) + Cr2O72-(aq) _ H3PO4 (aq) + Cr3+(aq)1 Label the oxidation numbers to the elements indicated in following speciesH3PO2 P _____ O _____Cr2O7 2- Cr _____H3PO4 H _____ P _____Cr3+ Cr _____2 Which element is reduced 3 Which is the reducing agent 4 Write and balance both half reactions in acid solution5 How many electrons are transferred in overall reaction 6 How many moles of H+ ions are involved in the overall balanced reaction
A solid sample containing some Fe2+ ion weighs 1000 g It requires7552 mL 00205 M KMnO4 to titrate the Fe2+ in the dissolved sample to a pink endpoint Consider the following net ionic equation for the reaction between MnO4- ionand Fe2+ ion in acid solution is 8H+(aq) + 5Fe2+(aq) + MnO4-(aq) _ 5Fe3+(aq) + Mn2+(aq) + 4H2O1 How many moles of MnO4- ion are required in the reaction2 How many moles of Fe+2 are there in the sample3 How many grams of iron are there in the sample4 What is the percentage of Fe in the sample
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Complete and balance the following chemical equations if a reaction occurs If no reaction occurs write No reactionI-(aq) + Cl2(aq) Br-(aq) + I2(aq)
What is the hydroxide ion molarity of a solution obtained by adding 130 g of NaOH to 795 mL of a 0200 M solution of Sr(OH)2 Assume no volume change after NaOH is added
A 1200 g sample of pure tartaric acid C4H6O6 (MM = 15008 gmol) requires 1866 mL of 0857 M potassium hydroxide for complete reaction How many moles of hydroxide ion are required to neutralize one mole of tartaric acid
A solution is prepared by mixing 0100 L of 0120 M sodium chloride with 0230 L of a 0180 M MgCl2 solution What volume of a 0200 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl
To titrate a 500 mL sample of a saturated aqueous solution of sodiumoxalate Na2C2O4 requires 2582 mL of 002140 M KMnO4 (aq) The balanced equation for the reaction is
5C2O42-(aq) + 2MnO4-(aq) + 16H+(aq) 1048774 2Mn2+(aq) + 8H2O(l) + 10CO2 (g)1 What is the molarity of sodium oxalate solution2 How many grams of sodium oxalate would be present in 2500 mL of the saturatedsolution
The number of moles of HCℓ in 10 mL of 12 M HCℓ is equal to thatin 1000 mL of 0012 M (Yes or No) 2 Solutions of silver sulfate and barium chloride are mixed Write the formula of the precipitate(s) that form(s) If no precipitate forms write NR3 Classify HCℓO3 as strong acid weak acid strong base or weak base4 C6H5NH2 is an Arrhenius acid when added to water (Yes or No)5 Acetic acid and sodium hydroxide are combined What are the spectator ion(s)
Write the net ionic equations for the reactions between aqueous solutions of the following compounds (Do not forget to indicate the physical states)
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
1 HCN(aq) and KOH(aq)2 Na3PO4(aq) and Ba(OH)2(aq)3 NH3(aq) and HCℓ(aq)
Ten milliliters of a 0250 M solution of Aℓ2(CO3)3 is mixed with 250 mL of a 0012 M solution of K2CO31 How many moles of CO32- ions are present in the final mixture2 What is the molarity of CO32- ions in the final solution (Assume the volumes are additive)
A sample of limestone weighing 1005 g is dissolved in 7500 mL of 02500 M hydrochloric acid The following reaction occurs CaCO3(s) + 2H+(aq) rarr Ca2+(aq) + CO2(g) + H2O(l) It is found that 1850 mL of 0150 M NaOH is required to titrate the excess HCℓ left after reaction with the limestone1 How many moles of hydrochloric acid are used 2 How many grams of CaCO3 (MM = 10009 gmol) are there in the sample3 What is the mass percent of CaCO3 in the limestone
E What is the volume of 02500 M cobalt (III) sulfate Co2(SO4)3 required to react completely with 1120 mL of 145 M sodium carbonate to form cobalt (III) carbonate
Three experiments are performed(A) Ca(OH)2 is mixed with HF(B) NaOH is mixed with Mg(NO3)2(C) Cu reacts to form Cu2+Write the letter of the experiment(s) that answers each of the following questions Ifnone of the experiments applies write NONE1 Which experiment involves a strong acid2 Which experiment produces a precipitate3 Which experiment involves a strong base4 Which experiment involves Cu as an oxidizing agent5 Which experiment produces water as a product
Iodine reacts with thiosulfate ion S2O32- to give iodide ion and the tetrathionate ion S4O6 2- The balanced equation for the reaction that takes place isI2(aq) + 2S2O3 2-(aq) rarr 2I-(aq) + S4O6 2-(aq) If 250 g of iodine is dissolved in enough water to make 150 L of solution what volume of 0244 M sodium thiosulfate will be needed for complete reaction
A student weighs out 01965 grams of an unknown chloride into an
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Erlenmeyer flask and titrates it with AgNO3 using K2CrO4 as indicator To reach theendpoint 1724 mL of 01529 M AgNO3 is required1 What is the number of moles of chloride ion in the sample2 What is the mass of chloride in the sample3 Calculate the mass percent Cℓ- ion in the sample4 If the student read the molarity of the AgNO3 as 01259 M instead of the correctvalue would the calculated mass percent Cℓ- be LESS than or GREATER than orthe SAME as (CIRCLE ONE) the actual value5 If the student was past the endpoint of the titration when he took the final buretreading would the calculated mass percent Cℓ- be LESS than or GREATER thanor the SAME as (CIRCLE ONE) the actual value
A 0100 g sample of an unknown acid requires 1295 mL of 00857 M NaOH for neutralization to a phenolphthalein end point What is the molar mass of theunknown acid HA(aq) + OH-(aq) rarr 2H2O + A-(aq)
It is determined that the halogens rank as oxidizing agents in the following manner (weakest) I2 Br2 Cℓ2 (strongest) Write R if a reaction occurs NR if no reaction occurs and MI if more information is requiredBr2 solution + Br- solutionBr2 solution + Cℓ- solutionBr2 solution + I- solution
Consider the following balanced redox reaction The reaction is the basis for the permanganate titration used to determine the Fe in a sample8H+(aq) + MnO4-(aq) + 5Fe2+(aq) rarr Mn2+(aq) + 5Fe3+(aq) + 4H2O 21 g of an unknown iron salt are dissolved in water acidified with H3PO4 and titrated with a standardized KMnO4 solution A persistent pink color is observed after 78 mL of a 0250 M KMnO4 solution are used1 How many moles of MnO4- are used in the titration2 How many moles of Fe are present in the sample3 What is the mass percent of Fe in the sample
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
Ch 5Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required)1 The volume of one mole of hydrogen gas at STP is __ the volume of one mole of argon gas at STP3 A mixture of gases contains 3 mol Kr 2 mol Ar and 2 mol Ne The molefraction of Kr is __ the mole fraction of Ar 1 Two tanks of equal volume contain hydrogen and nitrogen respectively2 At the same temperature the pressure inside the hydrogen tank is ____the pressure in the nitrogen tank_______ 4 The mole fraction of chlorine in a mixture of gases is 040 The total of themole fractions of the other gases in the mixture is ____ 0601 After the pressure of one mole of gas is tripled (at constant temperature) its volume is three times greater than its original value2 The partial pressure of water vapor in a gas collected over water isindependent of the temperature3 A molecule of He at 100 ordmC and 1 atm pressure will have exactly the same speed as a molecule of N2 at the same temperature and pressure4 At a constant temperature and pressure CH4 gas will effuse twice as fast as SO2 gas5 You are given two tanks of equal volume each at the same temperature and pressure One contains H2 and the other He The tank containing the hydrogen has a larger number of molecules than the one containing helium
If 00129 mol of N2O4 (MM = 9202 gmol) effuses through a pinhole in acertain amount of time how many moles of NO (MM = 3001 gmol) would effuse in that same amount of time under the same conditions [Ans = 00226 moles]
You have three tanks of gas all of equal volume and at equal temperature Tank A has 100 mol CH4 Tank B has 100 mol He and Tank C has 100 mol CO2 Use the following terms to answer the questions below GT (greater than) LT (less than) EQ (equal to) or MI (more information needed)1 The pressure in Tank B __ the pressure in Tank C2 The average kinetic energy of the molecules in Tank A ___ the averagekinetic energy of the molecules in Tank C3 If an equal sized pinhole is made in each the rate at which the pressure inTank A will drop is ____ the rate at which the pressure will drop in Tank B4 If the contents of Tank B are transferred without loss to a new tank of halfthe volume (at the same temperature) the new pressure in Tank B will be__ the pressure in existing Tank C
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
5 The average speed of the molecules in Tank A is ___ the average speedof the molecules in Tank C6 The density of the gas in Tank B is ___ the density of the gas in Tank C
For questions 1- 4 Ammonia NH3 is the most important commercialcompound of nitrogen It can be produced by reacting nitrogen with hydrogen gas1 Ammonia is kept at 15degC in a 100 L flask with a pressure of 195 atm What is thepressure in the flask if the temperature is increased to 25degC2 Ammonia is stored in a cylinder with a movable piston at 25degC and 250 atm pressureWhat is the pressure in the cylinder if the temperature is increased to 45degC and thevolume occupied by the gas is halved3 How many grams of ammonia are produced if 785 L of ammonia is collected at -15degC and 593 atm pressure
4 What is the density of ammonia at 32degC and 745 mm Hg
Methanol CH3OH can be synthesized by the following reactionCO(g) + 2H2(g) CH3OH(g)How many moles of hydrogen gas measured at a temperature of 355 K and a pressure of 738 mm Hg is required to synthesize 232 moles of methanol
A 158 g sample of C2H3X3 (g) has a volume of 297 mL at 769 mm Hg and 35ordmC What is the atomic mass of element X [ANS = 35ish so Cl]
Consider two bulbs connected by a valve Bulb A has a volume = 2000 mL amp contains nitrogen gas at a pressure of 0500 atm Bulb B has a volume of 0785 L amp contains CO gas at a pressure of 140 atm What is the pressure in the two tanks after the valve is opened The volume of the connecting tube amp valve is negligible Nitrogen doesnrsquot react with carbon monoxide (Temperature stays constant) [ANS = 122 atm]
A student weighs an empty flask and stopper and finds the mass to be 55441g She then adds excess unknown liquid and heats the flask in boiling water bath at 100oC After all the liquid is vaporized she removes the flask from the bath stoppers it and lets it cool After it is cool she momentarily removes the stopper then replaces it and weighs the flask and condensed vapor obtaining a mass of 56513 grams The volume of the flask is 2158 mL The barometric pressure in the laboratory that day was 752 mm Hg What is the molar mass of the unkown in the flask
Answer the following questions A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and chlorine1 Which of the two gases exerts the greater pressure2 The molecules or atoms of which gas have the greater average velocity3 The molecules of which gas have the greater average kinetic energy
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
4 If a small hole were opened in the flask which gas would effuse more quickly
A sealed balloon is filled with 100 L of helium at 23degC and 100 atm The balloon rises to a point in the atmosphere where the temperature is -31 degC and pressure is 220 mm Hg What is the change in volume of the balloon as it ascends from 100 atm to a pressure of 220 mm Hg
An unknown gas has a density of 3164 gL at STP What is the molar mass of the gas
Nitrogen can react with steam to form ammonia and nitrogen oxide gasesA 200 L sample of nitrogen at 173degC and 772 mm Hg is made to react with an excessof steam The products are collected at room temperature (25degC) into an evacuatedflask with a volume of 150 L What is the total pressure of the products in the 150 Lflask The balanced equation for the reaction that takes place is 5N2(g) + 6H2O(g) _ 4NH3(g) + 6NO(g)
A sample of neon effuses from a container in 76 seconds The sameamount of an unknown gas requires 155 seconds what is the molar mass of theunknown the gas [ANS = 841]
A flask with stopper weighs 6293 g About 5 mL of an unknown liquid isadded to the flask and it is heated in a boiling water bath at 100degC until the liquid hascompletely evaporated The flask is removed from the bath stoppered cooled andthen air is admitted to the flask at an atmospheric pressure of 745 mm Hg The massof the flask plus condensed vapor is 6349 g and the flasks volume is 2244 mL1 List the following parameters for the vapor of the unknown liquid at the momentwhen the flask is removed from the boiling water bath Write each answer with theproper number of significant figuresa What is the pressure of the vapor in the flask in atm b What is the volume of vapor in Liters c What is the temperature of the vapor in Kelvin d What is the mass of the vapor 2 What is the molar mass of the unknown liquid Give the answer in the proper number of significant figures
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
A gas in 20 L flask at 35degC has a pressure of 755 mm Hg What is the pressure of the gas in the same container if the temperature is increased to 75degC
At what temperature will a molecule of uranium hexafluoride the densest gas known have the same average speed as a molecule of the lightest gas hydrogen at 37degC
How many liters of O2(g) measured at 295 K and 763 mm Hg are consumed in the complete combustion of 255 L of dimethyl ether measured at 295 K and 478 mm Hg CH3OCH3(g) + 3O2(g) 1048774 2CO2(g) + 3H2O(l)
A quantity of N2 gas originally held at 475 atm pressure in a 100 L container at 20degC is transferred to a 100 L container at 20degC A quantity of O2 gas originally at 525 atm and 20degC in a 500 L container is transferred to this same container What is the total pressure in the new container
What increase in the Celsius temperature will produce a 50 increase in the volume of a sample of gas originally at 250ordmC if the gas pressure held constant
A compound has the simplest formula C2H2X2 A 2560 mL flask at 373 K and 7400 mm Hg contains 0789 g of the gaseous compound What is the atomic mass of the unknown element X [ANS = 355 Cl]
A metal hydride MH2 reacts with water per MH2(s) + H2O(ℓ) M(OH)2 (s) + 2H2(g)When 01232 g of MH2(s) reacts with water 2250 mL of dry H2(g) are produced at16degC and 09870 atm pressure Calculate the molar mass of MH2 amp identify the metal M [ANS = 24 g Mg]
Consider two different containers separated from each other by a valveBoth containers are at the same temperature Calculate the final pressure inside thesystem after the valve connecting the two containers is opened Ignore the volume ofthe tube connecting the two containersContainer A Container B Gas Ar O2 V 20 L 30 L P 10 atm 20 atm T 25ordmC 25ordmC
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
If a 00250 mol of NO effuses through a pinhole in a certain amount of timehow much N2O4 would effuse in that same amount of time under the same conditions
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
The Rydberg formula for the energy levels of the electron in a hydrogen atom is En = - RHn2 where RH = 2180x10-18 J The Brackett series includes transitions from nhi nlo = 41 What is the wavelength of the lowest energy transition of the Brackett series2 A line in the Brackett series (nlo = 4) occurs at 2624 nm Calculate nhi for thetransition associated with this line
Which of the following ions with electrons in their ground (lowest energy) states will have MORE than one UNPAIRED electron Ti+3 Ge+3 Cr+3
A photon of light has a wavelength of 423 nm (1 nm = 1 x 10-9 m)1 What is the frequency of the light2 What is the energy associated with that wavelength in kilojoules per moleConsider a transition in an atom for which nlow = 1 and nhigh = 2 The energy of this transition is calculated at 220 kJmol The energy of the transition from n = 2 to n = 3 will also be 220 kJmol
2 The energy of a photon of blue light (_ = 475 nm) is lower in energy than that of one of red light (_ = 650 nm) T or F3 The frequency of a wave is directly proportional to the speed at which the wave is traveling T or F
4 When n = _ H exists as H+
What is the wavelength (_ in nm) of the light wave associated with a frequency of 462 x 1014 s-1
Using the Bohr model what is the energy (in J) associated with a transition from the n = 2 to the n = 5 level
A helium-neon laser emits light at 6328 nm The bond enthalpy of IBr is 180 kJmol1 Does a helium-neon laser photon have enough energy to break that bond
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
2 What is the enthalpy of the strongest bond which such a photon could break
A laser in a compact disc player produces light with a wavelength of 780 nm (1 m = 1 x 109 nm)1 What is the frequency of the light2 What is the energy of this radiation in kilojoules per mole
Answer the questions below using LT (for is less than) GT (for is greaterthan) EQ (for is equal to) or MI (for more information required) in the blanks provided1 The wavelength of the photon required to promote an electron in thehydrogen atom from the n = 2 to the n = 3 level is __(1)___ thewavelength of the photon required to promote an electron in thehydrogen atom from the n = 1 to the n = 2 level2 For a titanium atom in the ground state the energy of the 3d sublevelis __(2)__ the energy of the 4s sublevel3 The 1048774 quantum number of the 3d sublevel is __(3)___ the 1048774 quantumnumber of the 5d sublevel4 The energy of the 3p orbital with m1048774 = -1 is ___(4)___ the 3p orbitalwith m1048774 = +1 in a P atom
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
1 Two objects a potato and a metal pan are removed from a 450degF oven Ifthe masses are equal which will cool to room temperature more quickly(take the specific heat capacity of the pan to be 0335 Jg-C and that of thepotato to be about 418 Jg-C) For the next four questions consider a solution prepared from 1000 g of NaOH in enough water to make 100 L 106 kJ of heat is evolved2 When the solid is dissolved the temperature of the solution rises Thereaction is endothermic (truefalse)3 The sign of H for this process is ____________4 What is q for the dissolving of 250 g of NaOH to a total volume of 100 L5 What is q for the dissolving of one mole of NaOHB (7 points) When 500 g of chromium at 2300ordmC absorbs 625 J of heat the temperature increases to 508ordmC What is the specific heat of chromium
C (8 points) Consider the following reaction for the combustion of propane C3H8C3H8(g) + 5O2(g) 1048774 3CO2(g) + 4H2O(g) ΔH = -2044 kJ1 How many moles of propane are necessary to produce 612 x 105 kJ of heat2 How many moles of CO2 are produced if 15 x 103 kJ of heat is liberated
(10 points) Zinc metal reacts with hydrochloric acid according to the following balanced equation Zn(s) + 2HCl(aq) ZnCl2(s) + H2(g) When 0103 g of Zn(s) is combined with enough HCl to make 500 mL of solution in a coffee-cup calorimeter all of the zinc reacts the temperature of solution changes from 225ordmC to 237ordmC Assume that the density of solution is 100 gmL and specific heat of the solution is 418JgmiddotordmC1 What is the heat of the reaction
2 What is the enthalpy change for the reaction written as above
E (6 points) Given the following reactionsCa(s) + 12O2(g) + CO2(g) CaCO3 (s) ΔH = -8128 kJ2Ca(s) + O2(g) 2CaO (s) ΔH = -12698 kJWhat is ΔHreaction for the reaction belowCaO(s) + CO2(g) CaCO3(s)
(8 points) Consider the following thermochemical data2P (s) + 3Cℓ2 (g) 2PCℓ3 (ℓ) ΔHdeg = -636 kJPCℓ3 (ℓ) + Cℓ2 (g) PCℓ5 (s) ΔHdeg = -138 kJ
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
1 Write a balanced chemical equation for the formation of one mole of PCℓ5 (s) fromits elements
2 Calculate degfΔΗ for PCℓ5 (s)
H (10 points) Using the data provided below answer the following questionsSpecific heat for bromine 0474 JgsdotdegCdegvap ΔH for bromine 296 kJmol Boiling point 590 degC1 Calculate the amount of heat involved in changing 150 g of liquid bromine Br2 atroom temperature (ℓ 225 degC) to liquid bromine at 590degC (ℓ 590degC)2 Calculate ΔH involved in changing 150 g of liquid Br2 (ℓ 590 degC) to vapor at590degC
(12 points) When ammonia reacts with dinitrogen oxide gas liquid water and nitrogengas are formed Values for Δ degf H are given below reactants and products 2NH3 (g) + 3N2O (g) 1048774 3H2O (ℓ) + 4N2 (g) Δ degf H (kJmol) -461 8205 -28551 What is the enthalpy change for the reaction2 What is the enthalpy change for a reaction that produces 00133 mol of nitrogengas3 Is heat evolved or absorbed
A coffee-cup calorimeter contains 500 g of water at 6051ordmC A 124 g piece of graphite at 2421ordmC is placed in the calorimeter The final temperature of the water and the carbon is 5902ordmC Calculate the specific heat of carbon The specific heat of water is 418 JgmiddotordmCA 0328 JgmiddotordmCB 0639 JgmiddotordmCC 0692 JgmiddotordmCD 0721 JgmiddotordmCE 139 JgmiddotordmC
2 Determine the enthalpy of reaction for the decomposition of calcium carbonate CaCO3(s) 1048774 CaO(s) + CO2(g) given the following thermochemical equationsCa(OH)2(s) 1048774 CaO(s) + H2O(l) ΔH = 652 kJCa(OH)2(s) + CO2(g) 1048774 CaCO3(s) + H2O(l) ΔH = -1132 kJC(s) + O2(g) 1048774 CO2(g) ΔH = -3935 kJ2Ca(s) + O2(g) 1048774 2CaO(s) ΔH = -12702 kJA 480 kJB 1784 kJ
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
3 Determine the enthalpy of formation of calcium carbonate from thethermochemical equations given above in problem 2 (IIIA2)A -1784 kJB -4932 kJC -8287 kJD -9806 kJE -12070 kJ
4 All of the following statements are true EXCEPTA the enthalpy change of an endothermic reaction is positiveB ΔH for a reaction is equal in magnitude but opposite in sign to ΔH for the reverse reactionC enthalpy is a state functionD enthalpy change is dependent upon the number of steps in a reaction
(10 points) Consider the following thermochemical equation for the formation of diboron trioxide from pentaborane B5H9(g) 2B5H9(g) + 12O2(g) 1048774 5B2O3(s) + 9H2O(l) ΔH = -90152 kJ1 Given that ΔHdegf for pentaborane is 6276 kJmol and ΔHdegf for liquid water is-2858 kJmol what is ΔHdegf for B2O32 Assuming 100 yield how much heat is given off when 500 L of air (21O2 byvolume) at 756 mm Hg and 250 degC reacts with an excess of pentaborane When 100 g of acetylene C2H2 is burned 482 kJ of heat is given off When 0750 g of acetylene is burned in a bomb calorimeter (heat capacity = 1117 kJdegC) the final temperature of the bomb calorimeter is 545degC What is the initial temperature of the calorimeter when reaction is complete
In a coffee cup calorimeter 500 mL of 0100 M AgNO3 and 500 mL of0100 M HCl are mixed to yield the following reaction Ag+(aq) + Cl-(aq) 1048774 AgCl(s)The two solutions were initially at 2260degC and the final temperature is 2340degCAssume that the specific heat of the solution is 407 JgmiddotdegC and that the combinedsolution is 1000 g1 Calculate the heat that accompanies this reaction in kJmol of AgCl formed2 How many moles of AgCl are obtained from the reaction3 What is the enthalpy change per mole of AgCl
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
(12 points) Instant cold packs often used to ice athletic injuries on the field containammonium nitrate and water separated by a thin plastic divider When the divider isbroken the ammonium nitrate dissolves according to the following endothermicreactionNH4NO3(s) 1048774 NH4+(aq) + NO3-(aq)1 Calculate the standard enthalpy change for the reaction using the following datadeg Δ f H (NH4NO3) = -3656 kJmol deg Δ f H (NH4+(aq)) = -1325 kJmoldeg Δ f H (NO3-(aq)) = -2050 kJmol
2 125 g of NH4NO3 is dissolved in enough water to make 250 mL solution at 200ordmCCalculate the temperature reached by the solution Use 10 gmL as the density ofthe solution and 418 JgdegC as the specific heat capacity
3 For the reaction the following reaction 2H2(g) + O2(g) 1048774 2H2O(ℓ) the enthalpy change is -2858 kJmol The enthalpy of formation of H2O(g) is _________ -2858 kJmol4 A sample of iron (specific heat 0450 JgmiddotdegC) and a sample of water(specific heat = 418 JgmiddotdegC) with equal masses each absorbs 200 J of
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
heat ΔT for the iron is _________ ΔT for the water5 The heat capacity of a block of iron (specific heat 0450 JgmiddotdegC) weighing 250 kg is _________ 847 X 102 JdegC
1 For the process 2Bi(s) + 3Cℓ2(g) rarr 2BiCℓ3(s) ΔHdeg = -7582 kJ Calculate ΔHdeg for the reaction belowBiCℓ3(s) rarr Bi(s) + 32C ℓ2(g)A +273 kJ B -273 kJ C +3791 kJ D 15164 kJ E -3791 kJ
2 Given the following equations and ΔΗdeg values determine the heat of reaction at 298 K for the reactionC2H2(g) rarr 2C(s) + H2(g) ΔHdeg =C2H2(g) + 52O2(g) rarr 2CO2(g) + H2O (ℓ) ΔHdeg = -12995 kJH2(g) + 12O2(g) rarr H2O(ℓ) ΔHdeg = -2858 kJC(s) + O2(g) rarr CO2(g) ΔHdeg = -3935 kJA -6202 kJ B +6870 kJ C -19788 kJ D -2267 kJ
3 Using the standard enthalpies of formation calculate the standard enthalpy change for the following reaction Mg(OH)2(s) + 2NH4+(aq) rarr Mg2+(aq) + 2NH3(g) + 2H2O(ℓ)A 589 kJ B -5180 kJ C -2604 kJD -4350 kJ E -2583 kJ
C (6 points) A 2250 g sample of water at 250degC is added to 3340 g of water at 150degC in a thermally insulated container What will be the final temperature of waterStandard enthalpy of formation (kJmol)Mg(OH)2(s) -9245NH4+(aq) -1325Mg2+(aq) -4668NH3(g) -461H2O(ℓ) -2858
D (10 points) Consider the following reaction for the combustion of phenol A 1800 grams sample of phenol C6H5OH (MM = 9011 gmol) was burned in excess oxygen in a bomb calorimeter The temperature of the calorimeter plus contents rose from 2136degC to 2637degC The heat capacity of the calorimeter and contents was 1166 kJdegC C6H5OH(ℓ) + 7O2(g) rarr 6CO2(g) + 3H2O(ℓ)1 What is the value of q for the reaction mentioned above2 Is the reaction exothermic(Yes or No)3 What is the value of q for the reaction when 1500 L of carbon dioxide at 25degC and100 atm is formed
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
D (5 points) Consider the following thermochemical equation2PbO (s) rarr 2Pb(s) + O2(g) ΔHordm = 4380 kJ What is the heat of formation of PbO(s)
E (10 points) The following questions are related to the condensation of 13821 g sample of ethanol gas (C2H5OH) (MM = 4607 gmol) at 784degC to liquid ethanol at 250degC (Specific heat of C2H5OH (ℓ) = 243 JgsdotdegC enthalpy of vaporization = 386 kJmol and normal boiling point = 784degC)1 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(g 784degC) rarr C2H5OH(ℓ 784degC)2 What is the enthalpy change ΔH for 13821 g of ethanolC2H5OH(ℓ 784degC) rarr C2H5OH(ℓ 250degC)3 What is the overall enthalpy change in condensing 13821 g of ethanol gas at 784degC to 2500degC
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
(10 points) A wet shirt with 95 g water on it is hung to dry in a small room at 25degCwhere the partial pressure of water in the rooms air is initially 0020 atm The vaporpressure of water at 25degC is 0032 atm What is the minimum volume the room musthave to allow the shirt to completely dry
The triple point of water occurs at 001degC and 00060 atm Air containing0004 atm water vapor is cooled What condensed phase(s) form(s)A Liquid B Solid C Both liquid and solidTo answer questions 2 and 3 use the following phase diagram for carbon dioxide (notto scale)
_____ 2 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 35degCis cooled until a condensed phase forms What is the form of that condensed phase
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
A solid B liquid_____ 3 The critical point of CO2 occurs at 31degC and 73 atm Gaseous CO2 at 25degCis compressed until a condensed phase forms What is the form of that condensed phaseA solid B liquid_____ 4 HF has a higher boiling point 19degC than HCl -85degC What interaction isthe major factor for this differenceA dispersion forces B dipoles forces C hydrogen bonding
Waters ΔHvap = 407 kJmol At the top of a very high mountain water boilsat 77degC What is atmospheric pressure at the mountaintop
For the following question use (LT for less than GT for greater than EQfor equal to MI for more information needed)2 The vapor pressure of compound Q is 125 mmHg at 300K Given asealed flask with some liquid Q present the vapor pressure in the flaskis __ 125 mmHgB (10 points) ΔHvap(H2O) = 407 kJmol What is its vapor pressure at 50oC rememberingthat its normal boiling point is 100oC
C (10 points) For cyclohexane (MM = 841 gmol) the vapor pressure at 255degC is 1000 mm Hg 00500 grams of cyclohexane are placed in a 5000 mL flask at 255degC What is the mass of gaseous cyclohexane in the flask
