Chemistry 30S Crystal Growing Project Objective (What will I accomplish?) Work independently and apply the principles of solution chemistry to grow a crystal at home. Rationale (Why am I doing this?) To develop a working understanding of the following terms. • Solute • Soluble • Mixture e Unsaturated • Solvent • Insoluble • Heterogeneous • Saturated • Solution • Homogeneous • Precipitate • Supersaturated • Concentrated • Dilute • Aqueous • Crystal Procedure 1. Research and develop a procedure for growing a crystal at home. 2. Conference with the teacher to articulate your method and have it approved. 3. Display your crystal in a three dimensional exhibit. Due Date(s) Wednesday, November 5, 2008 Wednesday, November 5, Thursday, November 6, 2008 Thursday, November 2008 Monday, November 24, 2008 Bragging Rights Bonus Categories One bonus mark will be awarded to each student that wins a bragging rights category, as determined by a class vote (silent auction method). No student may win more than one bragging rights title. No student may be awarded a bonus mark where the project mark would exceed 100%. The bonus mark in tied votes in any category will be split between no more than two winners, with each winner receiving one bonus mark. In the case of a three or more person tie in a single category winners will not be awarded a bonus mark.. NOTE: in case of disagreement, the final decision to award a bonus mark rests with the teacher. Timeline Project Stage Experimental Method 2. 3. Due Student & Teacher Planning Conferences Begin Growing Crystal 2008 4. Crystal Exhibit • Biggest crystal • Best decorated • Most functional looking • Most perfect looking • Smallest crystal • Most colourful • Greatest number of detached crystals • Coolest shape or design • Best display
Transcript
Chemistry 30S Crystal Growing Project
Objective (What will I accomplish?)Work independently and apply the principles of solution chemistry to grow a crystal athome.
Rationale (Why am I doing this?)To develop a working understanding of the following terms.
• Solute
• Soluble
• Mixture
e Unsaturated• Solvent
• Insoluble
• Heterogeneous • Saturated• Solution
• Homogeneous • Precipitate
• Supersaturated• Concentrated • Dilute
• Aqueous
• Crystal
Procedure1. Research and develop a procedure for growing a crystal at home.2. Conference with the teacher to articulate your method and have it approved.3. Display your crystal in a three dimensional exhibit.
Due Date(s)
Wednesday, November 5,2008
Wednesday, November 5,
Thursday, November 6,2008Thursday, November2008Monday, November 24,2008
Bragging Rights Bonus CategoriesOne bonus mark will be awarded to each student that wins a bragging rights category, asdetermined by a class vote (silent auction method). No student may win more than onebragging rights title. No student may be awarded a bonus mark where the project mark
would exceed 100%. The bonus mark in tied votes in any category will be split betweenno more than two winners, with each winner receiving one bonus mark. In the case of athree or more person tie in a single category winners will not be awarded a bonus mark..NOTE: in case of disagreement, the final decision to award a bonus mark rests with theteacher.
Timeline
Project Stage
Experimental Method
2.
3.
DueStudent & TeacherPlanning Conferences
Begin Growing Crystal
2008
4. Crystal Exhibit
• Biggest crystal
• Best decorated
• Most functionallooking
• Most perfectlooking
• Smallest crystal
• Most colourful• Greatest number of detached
crystals
• Coolest shape or design
• Best display
Chemistry 30S Crystal Growing Project
PLANNING CONVERSATIONIntermediateExpert
4 points)
(3-2 points
CRYSTAL GROWING PROJECT ASSESSMENT RUBRIC
Novice1-0 point
Name:
Criteria
Articulates amethod
Student articulates amethod personalized
to their homeenvironment to
successfully grow acrystal that requires
no revisions
Student articulates amethod to
successfully grow acrystal that requiresminor revisions (3)
or the studentrequires furtherinformation toarticulate their
method (2)
Student is unable toarticulate a method
(0) or presents amethod that clearly
has not been thought Iout and/or is not
personalized to theirenvironment (1)
CRYSTAL EXHIBITMinimum of threepictures illustratingdiverse stages of
One (3) or two (2)Pictures of growing
growth including
aspects of expertstages displayed
some method of
level criteriameasurement clearly
missingvisible with date
stampsInformation aboutthe chemical used,the growing time,
the biggestchallenge, and the
Crystal Display
most rewarding
Two (2) or three (3)Information
experience
criteria metassociated with
growing the crystali is communicated in
the display
' attractive, three- Two (2) or three (3)dimensional display
criteria metincluding crystal j
Colourful,
Crystal Display
More than twoaspects of expert
level criteriamissing (1) or no
pictures displayedof growing stages
(0)
Less than twocriteria met (1) or
no displayinformation present
(0)
Only one criteriamet (1) or no crystal
displayed (0)
/16
Chemistry 30S Silent Auction Ballots
Voting InstructionsCut out each ticket. Cast your ballot by placing each ticket in the appropriate container.
Pvtili; is sometimes labelled as "honoae-nized," meaning that the cream: is equal 'ydistributed throughout the milk. This use ofthe word does not match the chemistry defi-nition of homogeneous. Using the strictchemistry deuniton, milk is not a hor<;eae-
neous mixture, but a heterogeneo s mixture.WK is not a solution.
a homogeneous mixture of sub-stances composed of at least one solute andone solvent
a uniform mix-tore of only one phase
a substance that is dissolved in asolvent {e.g., salt, NaCl)
the medium in which a solute isdissolved; often the liquid component of asolution )e.g., water)
Figure 1Gasoline, shown here in a spill on asphalt, isa nonaqueous solution containing many dif-ferent solutes (mostly hydrocarbons such asbenzene and paraffin) in an octane solvent.The composition of gasoline is not fixed: itvaries with the source of the raw material,the manufacturer, and the season.
Many of the substances that we use every day come packaged with water, We buyother substances with little or no water, but then mix water with them before use.For example, we may purchase syrup, household ammonia, and pop with wateralready added, but we mix baking soda, salt, sugar, and powdered drinks withwater, Most of the chemical reactions that you see in high school occur in a waterenvironment. Indeed, most of the chemical reactions necessary for life on ourplanet occur in water.
Because so many substances dissolve in it, water is often referred to as theuniversal solvent. Of course, this is an exaggeration. Not all things dissolve inwater. Imagine if they did; we would not be able to find a container for water.
Before restricting our study to mixtures involving water, we will review themore general definition and types of a solution.
Solutions
Solutions are homogeneous mixtures of substances composed of at least onesolute and one solvent. Liquid-state and gas-state solutions are clear (trans-parent)-you can see through them; they are not cloudy or murky in appear-ance. Solutions may be coloured or colourless. Opaque or translucent (cloudy)mixtures, such as milk, contain undissolved particles large enough to block orscatter light waves. These mixtures are considered to be heterogeneous.
It is not immediately obvious whether a clear substance is pure or is a mix-
ture, but it is certainly homogeneous. Homogeneous mixtures in the liquid stateand the gas state are always clear with only one phase present. If you were to doa chemical analysis of a sample of a homogeneous mixture (i.e., a solution), youwould find that the proportion of each chemical in the sample remains the same,regardless of how small the sample is. This is explained by the idea that there is auniform mixture of particles (atoms, ions, and/or molecules) in a solution.
Empirically, a solution is homogeneous; theoretically, it is uniform at the atomicand molecular level,
Both solutes and solvents may
be gases, liquids, or solids, pro-
Table 1: Classification of Solutionsducing a number of different com-binations (Table 1). In metal alloys,
such as bronze or the mercuryamalgam used in tooth fillings, thedissolving has taken place in liquid
form before the solution is used insolid form. Common liquid solu-
tions that have a solvent other thanwater include varnish, spray furni-ture polish, and gasoline. Gasoline,
for example, is a mixture of as manyas 400 different hydrocarbons andother compounds (Figure I.). Thesesubstances form a solution-a
homogeneous mixture at the molecular level. There are many such hydrocarbon
solutions, including kerosene (a Canadian-invented fuel for lamps and stoves),and turpentine (used for cleaning paintbrushes). Most greases and oils will dis-solve in hydrocarbon solvents.
Solutein solvent Example of solution
gas in gas oxygen in nitrogen (in air)
gas in liquid oxygen in water (in most water)
gas in solid oxygen in solid water (in ice)
liquid in gas water in air (humidity)
liquid in liquid methanol in water (in antifreeze)
liquid in solid mercury in silver (in toothfillings)
solid in liquid sugar jr) water (in syrup)
solid in solid tin in copper in bronze)
266 Chapter 6
6.1
Other examples of liquids and solids dissolving in solvents other than waterinclude the many chemicals that dissolve in alcohols. For example, solid iodinedissolved in ethanol (an alcohol) is used as an antiseptic (Figure 2), Aspirin(acetylsalicylic acid, ASA) dissolves better in methanol (a poisonous alcohol)than it does in water, for example, when doing chemical analyses. Of course, itshould never be mixed with alcohol when ingested. Some glues and sealantsmake use of other solvents: acetic acid is used as a solvent of the components ofsilicone sealants. You can smell the vinegar odour of acetic acid when sealingaround tubs and fish tanks.
The chemical formula representing a solution specifies the solute by using itschemical formula and shows the solvent by using a subscript. For example,
Nil3(.3„
ammonia gas (solute) dissolved in water (solvent)
NaCl(,q)
solid sodium chloride (solute) dissolved in water (solvent)
I2(at)
solid iodine (solute) dissolved in alcohol (solvent)
CnHSOH(aq)
liquid ethanol (solute) dissolved in water (solvent)
By far the most numerous and versatile solutions are those in which water isthe solvent (Figure 3). Water can dissolve many substances, forming manyunique solutions. All aqueous solutions have water as the solvent and are clear(transparent). They may be either coloured or colourless. Although water solu-tions are all different, they have some similarities and can be classified ordescribed in a number of ways. This chapter deals primarily with the character-istics of aqueous solutions.
Properties of Aqueous Solutions
Compounds can be classified as either electrolytes or nonelectrolytes.Electrolytes are solutes that form solutions that conduct electricity. At this pointwe will restrict ourselves to compounds in aqueous solutions. Compounds areelectrolytes if their aqueous solutions conduct electricity. Compounds are non-electrolytes if their aqueous solu-
tions do not conduct electricity.Most household aqueous solutions,such as fruit juices and cleaningsolutions, contain electrolytes. Theconductivity of a solution is easilytested with a simple conductivityapparatus (Figure 4) or an ohm-meter. This evidence also provides adiagnostic test to determine theclass of a solute---electrolyte ornonelectrolyte. This very broadclassification of compounds intoelectrolyte and nonelectrolyte cate-gories can be related to the maintypes of compounds classified inChapter 2. Electrolytes are mostlyhighly soluble ionic compounds
(e.g., KBr,agl), including bases such as
Figure 4ionic hydroxides (e.g., sodium hyd.rox-
The bulb in this conductivity apparatus lights
ide, NaOH(;pct}). Most molecular
up if the solute is an electrolyte.
Figure 2tincture of iodine is a solution of the element
iodine and the compound potassium or sodiumiodide dissolved in ethanol. It is used to pre -
vent the infection of minor cuts and scrapes.
a solute dissolved inwater
Figure 3Concentrated hydrochloric acid soften sold
under its common name, muriatic acid) con-
taints hydrogen chloride gas dissolved in
water. It is used to etch concrete before
painting it, clean rusted metal, and adjust
acidity in swimming peals,
a compound that, in anaqueou utio,n, conducts el ectricity
compound that, in anaqueous solution, does not conduct electricity
Ilse Nature afad Properties of Solutions 267
6.1
1. Carry out your Procedure, recording your observations in a suitableformat.
(d) Using the evidence you have collected in your experiment, answer theQuestion: Which of the white solids labelled 1, 2, 3, and 4 is calcium chlo-ride, citric acid, glucose, and calcium hydroxide?
(e) Evaluate the evidence by critiquing the Experimental Design, Materials,and Procedure. Look for any flaws, sources of error, and possible improve-ments. Overall, how certain are you about your answer to the Question?
Understanding Concepts
1. Classify the following mixtures as heterogeneous or homogeneous.Justify your answers.(a) fresh-squeezed orange juice(b)
(e)
(d)
(e)
(f)
(g)
(h)
(i)
white vinegarred winean antique bronze daggera stainless steel knifean old lead water pipehumid aira clouda dirty puddle
2. Which of the following are solutions and which are not solutions?(a) milk(b) apple juice(c) the gas in a helium-filled balloon(d) pop(e) pure water
(f) smoke-filled air(g) silt-filled water
(h) rainwater(i) 14K gold in jewellery
3. State at least three ways of classifying solutions.
4. (a) What is an aqueous solution?(b) Give at least five examples of aqueous solutions that you can
find at home.
5. Using the information in Table 3, classify each of the compounds aseither an electrolyte or a nonelectrolyte. Provide your reasoning.
6. (a) What types of salutes are electrolytes?(b) Write a definition of an electrolyte.
7. Describe the salutes in the following types of solutions:(a) acidic(b) basic(c) neutral
8. Electrolytes are lost during physical activity and in hot weatherthrough sweating. The body sweats in order to keep cool-cooling by
Table 3
Compound Classmethanol molecular
sodium chloride highly soluble ionic
hydrochloric acid acid (molecular)
potassium hydroxide base (ionic hydroxide)
The Nature and Properties of Solutions 269
GRADE 11 CHEMISTRY • Topic 4: Solutions
SK]LLS AND ATriTUDES OUTCOMES
C11-0-U1: Use appropriate strategies and skills to develop an understanding of chemical concepts.
C11--R1: Synthesize information obtained from a variety of sources.
In lode: print and electronic spec€atsts, orther resource people
with a small crystal seed placed at the bottom. The crystal solid that results willform a tall column in the beaker if poured slowly. The column. is fragile.
TEACHER NOTES
Most chemical reactions occur in an aqueous medium, and not in the solid, liquid,or gaseous phase. Students should be familiar with the nine types of solutionspresented below and should be able to provide an example for each. Emphasize thatthe smaller amount in a solution is usually classified as the solute and the largeramount the solvent. Ask students to provide examples other than those presentedbelow.
Types of Solutions
Solution Example
solid in solid copper in silver (sterling silver)•
zinc in copper (brass)
solid in liquid salt in water (ocean water)•
iodine in alcohol (tincture)solid in gas microscopic particulates in air
mothball particles in air
liquid in solid mercury in silver amalgams (tooth fillings)*
liquid in liquid •
ethylene glycol in water (engine antifreeze)•
methanol in water (gas line antifreeze)
liquid in gas •
water vapour in air
gas in solid •
hydrogen in palladium** (purification of hydrogen)•
poisonous gases adsorbed in carbon (charcoal filter)
gas in liquid •
carbon dioxide in beverages (carbonated beverages)•
oxygen in water (supporting aquatic life)
gas in gas oxygen in nitrogen (air)
Have students ask their dentists to explain the use of a known carcinogen in an amalgam fororal/dental use.
** At room temperature, palladium will absorb 900 times its own volume of hydrogen.
Journal Writing
Have students relate the demonstration/discrepant event in their journals. Students
could also include their dentists' explanation of the use of a known carcinogen in anamalgam for oral/dental use (as a follow-Lip).
Topic 4: Solutions - 5
Dissolving of Molecular and Ionic Compounds
Sucrose dissolved in water
The dissociation of
sodium chloride
into positive and
negative ions
CQ Copyright 2002 Nelson Thomson Learning
29
Intermolecular Forces and Dissolving
Polar solute molecules (in red) are surrounded by polarsolvent molecules (in green).
H-0:------- H---N-H------- :0-H
H
H
H
:0-H
H
Multiple hydrogen bonds between ammonia and water result ina very high solubility for ammonia.
o Copyright 2002 Ne'son Thomson Learning
28
SOLUTIONS: TYPES OF SOLUTIONS
Objective: Differentiate among unsaturated, saturated, and supersaturated solutions.
Equipment and Chemicals:
Lab Setup:
1. Burner
2. 250 mlbeaker
3. Test tube holder 4. Dropper pipet5. Small test tubes
(3)6. 1- lint striker
7. sodium thiosulfate pentahydratecrystals
Safety:1. Wear safety goggles over your eyes2. Observe all glassware precautions3. Observe all fire precautions4. Clean up all spills immediately5. Rinse affected areas with lots of running water6. Sodium thiosulfate pentahydrate may be harmful if swallowed and may cause
irritation to skin, eyes, and mucous membranes.7. Wash your hands with soap and water after conducting the experiment.
Procedure:
1. Obtain all materials.
2. Label three test tubes A, B. and C.3. Half fill test tube A with sodium thiosulfate pentahydrate crystals. Return to your
lab station.4. Remove 5 crystals and set aside. Pour half of the remaining sodium thiosulfate
pentahydrate into test tube B.5. Place two of the 5 reserved crystals into test tube C.6. Add one half complete dropper pipet of water to each test tube. Drum test tubes
B and C with your fingers to dissolve each solution.7. Clamp test tube A with test tube holders and gently heat in a burner flame for 3 to
5 seconds at a time. Use the proper technique for heating and mixing as describedto you by the instructor.
S. Fill a 250 mL beaker with about 175 mL of cold tap water. Gently place each testtube into the cold water to cool. Wait three minutes. Do not agitate any of thesolutions.
9. One at a time, remove each test tube from the water bath, dry the outside withpaper towel, and insert a single crystal into the solution. Hold the bottom of eachtest tube in your hand. Record your observations.
10. Drum test tubes B and C on your fingers in an attempt to dissolve the crystal.11. Dissolve any solids remaining in the test tubes and rinse down the sink with lots
of water.12. Rinse all remaining glassware with lots of tap water and put all equipment away.
SOLUTIONS: TYPES OF SOLUTIONS
Observations:Test Tube A
Test Tube B
Test Tube C
Questions:1. Identify which solutions are unsaturated, saturated, and supersaturated.
2. Describe the differences between unsaturated, saturated, and supersaturated solutions.
TYPES OF SOLUTIONS LAB RUBRICCriteria Novice Intermediate Exert
Student observes Student does not Student is naggedAll aspects of the
proper safety wear their safety once or more aboutlab are conducted in
precautions goggles or has a lab not following propera safe manneraccident safety precautions
Student follows Evidence that theEvidence that the
written and student has notstudent has not Student follows all
verbal followed more thanfollowed one written
written or verbal
instructions one written or verbalor verbal instruction instructions
instruction
Evidence of Little or no evidence Some evidence hat--a Evidence that all
equitable of equitable group member group members
participation participation by a participated more participatedgroup member than another equitably
More than one pieceEvidence of Entire station is
Lab station is of evidence remainschemicals or a piece cleaned up with no
cleaned up after of chemicals orof equipment remains evidence remaining
lab equipment afterafter cleanup of equipment or
I Cleanup chemicals
I
Solubility Curve of K 03
ObjectiveConstruct a solubility curve of potassium nitra
ChemicalsKNO3
• Tap water
SafetyDo not bum yourself on the hotplate. Be careful with glassware and thermometres.
Equipment•
Test tube
Temperature probe
•
Hotplate•
Test tube
•
10 mL graduated
•
250mL beakersholder
cylinder
(2)•
Dropper pipet
Procedure
1. Set up a water bath by filling a 250 mL beaker with approximately 175 mL of tapwater and carefully placing it on a hotplate. Set the hot plate to high. One groupmember should be consciously monitoring the water bath at all times.
2. Obtain all materials. Boot the computer, launch the software package, and set upthe temperature probe. Press the MON button to activate the sensor.
3. Place clean dry test tube in a clean 250 mL beaker.4. Label the test tube with an indelible marker if you are sharing a water bath.5. Obtain the appropriate mass of potassium nitrate in your test tube, as instructed by
your teacher.6. Fill a clean 10 mL graduated cylinder with 10.0 mL of tap water. Using a dropper
pipet, suction out 2.0 mL of water and add it to the test tube. Be sure to read themeniscus properly as directed by your instructor.
7. Insert the clean dry temperature probe into the test tube.8. Place the test tube with the probe in it into the hot water bath to dissolve the
KNO3. Monitor your solution and the cord to prevent any lab accidents.9. Once your solution has completely dissolved, using a test tube holder remove the
test tube from the water bath with the temperature probe still in it and place in theempty 250 mL beaker. Turn off the hotplate and unplug it. Carefully transportthe beaker and test tube to your lab station.
10. Continuously observe your solution with stirring as it cools, recording thetemperature at which crystals first begin to appear. Record the temperature in thetable below beside your corresponding mass of KNO3.
11. Repeat steps 7 to 9 as many times as possible in order to obtain precise results.12. To clean up, return your test tube and thermometer to the hot water bath. Allow
solutions to dissolve and empty them into the appropriate beaker for recycling.13. Rinse all equipment with lots of water and put it away,
www. pembinatrails.calshaftesburylmrdeakin " . adeakin rl,pembinatrails.ca2 (204) 888-5898 > Shaftesbury High School, 2240 Grant Ave, Wpg, MB, R3P OP7
Solubility Curve of KN03
Quantitative DataMass and Temperature Data or Saturated Potassium Nitrate Solutions
Mass of KNO3 (g) Volume of water (mL) Crystallization Temperature (°C)
Trial 1 Trial 2 Trial 3 Average
1.00
1.50
2.00
2.50
3.00
3.50
4.00
CalculationsShow a sample calculation of the conversion of grams KNO3 per volume of water tograms KNO3 per 100 mL water.
SOLUBILITY CURVE OF KNO 3 LAB RUBRICCriteria Novice Intermediate Expert
Student observes Student does not Student is naggedAll aspects of the
proper safety wear their safety once or more aboutlab are conducted in
precautionsgoggles or has a lab not following proper
a safe manneraccident safety
recautions
Student follows Evidence that thestudent has not Evidence that the
Student follows allwritten andfollowed more than student has not
written or verbalverbalone written or verbal
followed one writtenI
instructionsinstructions or verbal instructioninstruction
Evidence of Little or no evidence Some evidence that a Evidence that all
equitableof equitable group member group members
participation participation by a participated more participatedgroup member than another e uitably
More than one pieceEvidence of Entire station is
Lab station is of evidence remainschemicals or a plea,
cleaned up with nocleaned up after i of chemicals or
of equipment remainsevidence remaining
lab equipment afterafter cleanup of equipment or
cleanup
j 1 chemicals
www,pembinatra€Is.ca/shaftesbury/mrdeakin
adeakim,e pembinafrails,ca(204) 888-5898
Shaftesbury High School, 2240 Grant Ave, Wpg, MB, R3P 0P7
Solubility Curve of KNO3
Conclusion1) Construct and hand in a graph of mass of K-N,03 per 100 mL H2O on the y -- axis
versus temperature on the x - axis.2) Draw the curve of best fit.
Questions:
1) Describe the relationship between the solubility of KNO3 and the temperature ofthe solvent.
2) Using your graph, determine how many gram of KNO3 can be dissolved in 100grams of water at the following temperatures:
a) 35°C
b) 60°Cc) 70°C
Predict whether the following solutions of KNO3 would be considered saturated,unsaturated or supersaturated.
a) 75 g of KNO3 in 100 ml waterb) 60 g of KNO3 in 100 ml of water.
_-9 .. www. pembinatrails.ca/shaftesbury/mrdeakin -T,' ' adeakin r,pembinatraiis.ca(204) a88-5898 7. Shaftesbury High School, 2240 Grant Ave, Wpg, MB, R3P OP7
GRADE, 11 CHEMISTRY • Topic 4 Appendices
Solubility Curve
150
140
130
120
0 110T-
a, 100CC7
900)
80C3
° 70
60
0CO
a,
30
20
10
0
50
40
Solubility vs. Temperature for Several Substances
I
IT If}I
NaNO3
7-7I
NH C ,4
.......... ......[I
3
I
VNaCI
KCIO3
Ce2(S 4)3
10 20 30 40 50 60 70 80 90 100
Temperature (°C)
Topic 4 Appendices - 17
SVLUDILIJ-T %;UWVLSAnswer the following questions basedon the s'c blllty curve below.
1. Which salt Is least soluble in water
Name
5a40
30
20
10
0
at 20° C?
2, How many grams of potassiumchloride can be dissolved in 200 gof water at 80° C?
3. At 40° C, how much potassium
nitrate can be d tvedJn 3010. g of
water?
4. Which salt shows the least changeIn solubility from 0° - 100° C?
At 30° C, 90 g of sodium nitrate Is
dissolved in 100 g of water. Is this
solution saturated, unsaturated or
supersaturated?
:1::±^l -] I __M
20 30 40 50 60 70 80 90 100Temperature (0°C)
so
140
6. A saturated-solution-ofpotassium chlorate Is formed from one hundred grams ofwater. If the saturated solution Is cooled from 80° C to 50° C, how many grams ofprecipitate are formed?
7. What compound shows a decrease In solubility from 0° to 100° C?
8. Which salt Is most soluble at 10° C?
9. Which salt is least soluble at 50° C?
Which salt Is feast soluble at 900 C?
hemtstry IF8766
67
Clnstructloncal For. Inc.
Date
Class
Text Reference: Section 16.4
Name
CHAPTER 16 REVIEW ACTIVITY
solubility Curves
Study the solubility curves in the figure, and thenanswer the questions that follow.
1. What relationship exists between solubility
and temperature for most of the substancesshown?
2. a. What is the exception?
b. What general principle accounts for this ex-ception?
3. a. Approximately how many grams of NaNO3will dissolve in 100 g of water at 20°C?
b. How many grams will dissolve at 60°C?
4. How many grams of NH4CI will dissolve in1 dm3 of H2O at 50°C?
5. Ninety grams of NaNO3 is added to 100 g of H2Oat 0°C. With constant stirring, to what temperaturemust the solution be raised to produce a saturatedsolution with no solid NaNO3 remaining?
6. A saturated solution of KC103 was made with300 g of H2O at 40°C. How much KCIO3 could berecovered by evaporating the solution to dryness?
7. Five hundred grams of water is used to make asaturated solution of KCI at 10°C. How many moregrams of KCI could be dissolved if the tem-perature were raised to 100°C?
8. A saturated solution of KNO3 in 200 g of H2O at50°C is cooled to 20°C. How much KNO3 will pre-cipitate out of solution?
COPYRIGHT by Prentice Hill. Inc.Reproduction of this master is restricted to duplication for classroom use only.
CHEMISTRY: The Study of Matter
1&11
1.
2.a.
b.
240
I- 1 11 F" ^. ^ ^ ^ ^. ^ ^, 14-1 1::F;1-1 v
I 1111L.14-11- IAit 111 1111111 11 FVT-111
Poul1tojm Mrs
220
t
S 120
t 1. 1 L t. I f Lorl R
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I I I H^
k
!0 20 30 40 50 00 70 80 90 ro0
TTrrowa urI ("C)
poeaetiutn SUMAC
Temperature ('C)
,ON
SCIENCE
1. Calculate the maximum number of grams of each solute that can be dissolved:
J) potassium nitrate in 300 cm3
b) sodium chloride in 1250 arts
c) sodium nitrate in 50 cmm
of water at $0` C.
of water at 40' C.
of water at 00 C.
2. Calculate the minimum volume of water needed to dissolve;
'
a) 500 g of sodium chloride
b) 10.0 g of potassium nitrate
c) 1.001cg of sodium nitrate
in water at 100° C.
in water at 0' C.
I
in water at 50° C
3. Calculate the temperature the water must be to just dissolve;
a) $0.0 g of potassium nitrate
b) 60.0 g of potassium nitrate
in 200 cm3 of water.
in 50 cma of water.It
4. Calculate the mass of precipitate in each case below;
a) a saturated solution of sodium nitrate
in 400 cros of water at 100' C is made.The temperature is then changed to 13' C.
Shaftesbury High School, 2240 Grant Ave, Wpg, MB, R3P 0P7
Solubility Rules Lab
Objectives1. Examine the solubilities of pairs of ionic solutions in double displacement
reactions.2. Write balanced dissociation., overall ionic, and net ionic equations for precipitate
reactions.3. Verify the solubility rules.
Lab Setup
1. Paper towel
2. Aqueous solution of ions3. Watch glass 4. Tap water5. Glass stir rod
Chemicals1. 0.1 M AgNO3(aq)
4. 0.1 M Fe(N03)3(aq)
2. 0.5 M Pb(N03)2(aq) 3. 0.5 M K2Cr04(aq)5. 6.0 M NaOH(aq)
6. 0.5 M NaI(aq)
Safety• Wear safety goggles over your eyes at all times during the experiment• Clean up all spills immediately with copious quantities of tap water• Rinse affected areas with copious quantities of running tap water• All solutions are poisonous, AgNTO3 permanently stains skin and clothing dark brown,
and NaOH is corrosive, so observe appropriate precautions
Procedure1. Into a clean, dry watchglass, add two drops of your solution.2. Combine your solution with two drops of another solution. Mix with a clean, dry
stir rod. Record your observations.3. repeat steps I and 2 until you have combined your solution with every other
solution.4. Rinse all glassware with copious quantities of tap water, dry all equipment, and
return it to its original location.
Solubility Rules Lab
Data & Observations
Solution &Observation
BalancedDissociation
Eq uation
I Cations do NOTdissolve withthese Anions
Anions do NOTdissolve withthese Cations
12.
3
4.
5.f
[
3
6.
Balanced DIE, OIE, NIE
ConclusionExplain how the results of the experiment verify the solubility rules.
Molarity Practice Problems1) How many grams of potassium carbonate are needed to make 200 mL of a
2.5 M solution?
2) How many liters of 4 M solution can be made using 100 grams of lithiumbromide?
3) What is the concentration of a 450 mL solution that contains 200 grams of iron(Il) chloride?
4) How many liters of 0.88 M solution can be made with 25.5 grams of lithiumfluoride?
5) What is the concentration of a solution that has a volume of 2.5 L andcontains 660 grams of calcium phosphate?
6) How many grams of copper (II) fluoride are needed to make 6.7 liters of a 1.2M solution?
Making Solutions Practice Problems
Explain how you would make the following solutions. Your answer should be astatement, not just a number.
7) 2Lof6MHC1
8) 0.75 L of 0.25 M Na2SO4
9) 250 mL of 0.75 M lithium nitrite
10) 4.5 mL of 0.05 M magnesium sulfate
11) 90 mL of 1.2 M BF3
.Making a Solution Lab
Before you begin to obtain glassware and chemicals,know that EACH member of the group must check inwith Mr. Deakin 3 times during this experiment.
1. Show me your complete answer, including yourstatement - to the prompt:Explain how to make a 100.00 mL solution of 0.20
mol/L potassium nitrate.
2. Show me your dissolved solution BEFORE youpour it into the volumetric flask.
3. Show me how you lined the meniscus up with thegraduation mark on the neck of the volumetricflask BEFORE you invert and mix your solution.
Dilutions Practice Problems
12) if I have 340 mL of a 0.5 M NaBr solution, what will the concentration be if Iadd 560 mL more water to it?
13) If I dilute 250 mL of 0.10 M lithium acetate solution to a volume of 750 mL,what will the concentration of this solution be?
14) If I leave 750 mL of 0.50 M sodium chloride solution uncovered on awindowsill and 150 mL of the solvent evaporates, what will the newconcentration of the sodium chloride solution be?
15) To what volume would I need to add water to the evaporated solution inproblem 3 to get a solution with a concentration of 0.25 M?
DILUTING A SOLUTION LAB
Purpose:Prepare a 0.016 mol'L solution from 100.00 mL of 0.20 mol/L stocksolution of potassium nitrate.
Chemicals & Equipment:• 100.00 mL of 0.20 mol/L potassium nitrate
• Droppersolution
pipet• 150 mL beaker
• 50 mL beaker• Distilled water
• Funnel• 10 mL graduated cylinder
Procedure:1. Obtain all chemicals and equipment.2. Empty all of 0.20 mol /L stock solution into a 150 mL beaker.3. Rinse the volumetric flask 3 times with very small amounts of
distilled water. Fill 1/3 full with distilled water and set aside.4. Fill a 10.0 mL graduated cylinder with the correct amount of stock
solution. Use a dropper pipet to obtain a precise amount.5. Check your work with the instructor before moving on to the next
step.6. Pour the solution from the graduated cylinder into the volumetric
flask.7. Fill to just under the calibration mark.8. Put a very small amount of distilled water into a 50 mL beaker and
use the dropper pipet to rill the volumetric flask to the calibrationmark.
9. Stopper your solution and check with your instructor.10.Invert the solution 3 times to mix.11. Rinse all remaining solutions down the drain with lots of running
water, rinse remaining and put everything away.
DILUTING A SOLUTION LAB
Before you begin to obtain glassware and chemicals, EACHmember of the group must check in with Mr. Deakin 3 timesduring this experiment.
1. Show me your complete answer, including your statement-- to the prompt:Explain how to make a 100. 00 mL solution of 0.016 mol1L
potassium nitratefrom a 0.20 mol/L stock solution.
2. Show me a volumetric flask 1/3 full of water and agraduated cylinder filled with 10.0 mL of 0.20 mol/Lstock solution.
3. Show me how you lined the meniscus up with thegraduation mark on the neck of the volumetric flaskBEFORE you invert and mix your solution.
LUTING A SOLUTION LAB RumCriteria Novice Intermediate Expert
Student observes Student does not wear Student is nagged onceAll aspects of the lab
proper safety their safety goggles or or more about notfollowing proper safety are conducted in a safe
precautions has a lab accident mannerprecautions
Student follows Evidence that theEvidence that the
written and student has notstudent has not Student follows all
verbal followed more than onefollowed one written or written or verbal
[
instructions written or verbalverbal instruction instructions
iinstruction
Evidence of Little or no evidence of Some evidence that aEvidence that all
equitable equitable participation (Yroup membergroup members
participation by a group member participated more thanparticipated equitably
another[
M th i Entire station isLab station is
fore an one p ece oevidence remains of Evidence of chemicals cleaned up with no
cleaned up afterchemicals or equipment or a piece of equipment evidence remaining of
labafter cleanup remains after cleanup
? equipment orchemicals
Answers
2. 7.5% WV
3. 32% WN
4. 4.8% W;'W
5.8 mg
6. 5.4 ppm
7. (a) 1/1000
(c) 30µg
8. 1.8 mol/L
Understanding Concepts
1. What are three different ways of expressing the concentration of asolution?
2. Gasohol, which is a solution of ethanol and gasoline, is considered tobe a cleaner fuel than just gasoline alone. A typical gasohol mixtureavailable across Canada contains 4.1 L of ethanol in a 55-L tank offuel. Calculate the percentage by volume concentration of ethanol.
3. Solder flux, available at hardware and craft stores, contains 16 g ofzinc chloride in 50 mL of solution. The solvent is aqueous hydrochloricacid. What is the percentage weight by volume of zinc chloride in thesolution?
4. Brass is a copper-zinc alloy. If the concentration of zinc is relativelylow, the brass has a golden colour and is often used for inexpensivejewellery. If a 35.0 g pendant contains 13 g of zinc, what is the per-centage weight by weight of zinc in this brass?
5. If the concentration of oxygen in water is 8 ppm, what mass ofoxygen is present in 1 L of water?
6. Formaldehyde, CH2Orgi, is an indoor air pollutant that comes fromsynthetic materials and cigarette smoke. Formaldehyde is controver-sial because it is a probable carcinogen. If a 500-L indoor air samplewith a mass of 0.59 kg contained 3.2 mg of formaldehyde, this wouldbe considered a dangerous level. What would be the concentration offormaldehyde in parts per million?
7. Very low concentrations of toxic substances sometimes require theuse of the parts per billion (ppb) concentration.(a) How much smaller is 1 ppb than 1 ppm?(b) Use the list of equivalent units for parts per million to make a
new list for parts per billion.(c) Copper is an essential trace element for animal life. An average
adult requires the equivalent of a litre of water containing 30 ppbof copper a day. What mass of copper is this per kilogram ofsolution?
8. A plastic dropper bottle for a chemical analysis contains 0.11 mol ofcalcium chloride in 60 mL of solution. Calculate the molar concentra-tion of calcium chloride.
Making Connections
9. Toxicity of substances for animals is usually expressed by a quantitydesignated as "LDse." Use the Internet to research the use of thisquantity. What does LDS0 mean? What is the concentration in ppm fora substance considered "extremely toxic" and one considered"slightly toxic"?Follow the links for Nelson Chemistry 11, 6.3.
Reflecting
10. How is your report card mark in a subject like a concentration? Whatother ratios have you used that are similar to concentration ratios?
Calculations Involving ConcentrationsSolutions are so commonly used in chemistry that calculating concentrationsmight be the primary reason why chemists pull out their calculators. In associ-ated calculations, chemists and chemical technicians also frequently need to cal-
284 Chapter 6
6.3
Figure 5Aqueous ammonia is purchased for sciencelaboratories as a concentrated solution. Whatis the concentration of the solute?
14.8 viol
IL
2,5 L
2.5x 14.8 motI l
?z%" n = 37 mcl
The amount of ammonia present in the bottle is 37 mol.
You should always check that your answer makes sense. For example, inSample Problem 8, 14.8 mol/L means that there is 14.8 mol of ammonia in 1 Lof solution. Therefore, 2.5 L, which is greater than I L, must produce an amountgreater than 14.8 mol.
In some situations you may know the molar concentration and need to findeither the volume of solution or amount (in moles) of solute. In these situationsuse either the volume /amount or amount /volume ratio. Notice that the units ofthe quantity you want to find should be the units in the numerator of the con-version factor ratio.
What volume of a 0.25 mot/L salt solution in a laboratory contains 0.10 mol ofsodium chloride?
0,25 molI L
CN
nhaC1 = 0.10 mal
VNaCl ° 0.10IL
.25 pibtX
VivaCl ^ 0.40 L
You need 0.40 L of salt solution to provide 0.10 mol of sodium chloride.
Understanding Concepts11. Rubbing alcohol, C3H7QH,,), is sold as a 70.0% V/V solution for
external use only. What volume of pure C3H70HM is present in a 500-mL (assume three significant digits) bottle?
12. Suppose your company makes hydrogen peroxide solution with ageneric label for drugstores in your area. What mass of purehydrogen peroxide is needed to make 1000 bottles each containing250 mL of 3.0% WA' H202^agr?
13. The maximum acceptable concentration of fluoride ions in municipalwater supplies is 1.5 ppm. What is the maximum mass of fluorideions you would get from a 0.250-L glass of water?
Answers
11. 0.350 L
12. 7.5 kg
13. 0.38 mg
The Nature arnd Properties of Solt{ tions 287
CONCENTRATION QUESTIONS
1, Toothpaste contains 0.24 % w/ww, of sodium fluoride. If 0.50 g of toothpaste issqueezed onto a toothbrush, what mass of sodium fluoride is used'? (0.0012 g)
2. Zinc oxide is the main ingredient in sunscreen. A premium brand advertises itssunscreen contains 10 % w/v of zinc oxide. What size bottle contains 23 grams ofzinc oxide? (230 mL)
3. The maximum contaminant level of lead in drinking water is 15 ppb. Assuming awater source has 15 ppb of lead, what mass of lead are you drinking if youconsume 2 L of water a day? If lead accumulates in the fat cells of your body,how many grams of lead are in your body after 1 year? (3 x 10-5 g, 0.01095 g)
4. Tincture of iodine is used as a disinfectant for boo-boos. If 25 mg/mL ofpotassium iodide is dissolved in a bottle of iodine tincture, what percent by massis the solution? (2.5 % w/v)
5. Joanne drinks water containing 0.08 g of dissolved minerals. What concentrationin parts per million of minerals is present in a 500 mL bottle of water? (160 ppm)
DILUTION QUESTIONS
6. Natalie likes to feed the humming birds in her garden. If she dissolves 12 g of
fructose - chemical formula CoHi2O6 - in 250 mL of water, what is theconcentration of her sucrose solution? (0.27 moUL)
7. If humming birds are partial to a O.10 M solution of fructose and Natalie's birdfeeder only holds 100 mL of solution, how much of her original solution must shedilute to make a new 0.10 M solution? (37 mL)
Limiting Factor Questions
For each of the following pairs of solutions,a) write the balanced dissolving equations
b) write the balanced overall ionic equationc) write the balanced net ionic equation
d) calculate the concentrations of all ions in solutione) calculate the mass of the precipitate
125 mL of 0.25 M barium iodide solution and 75 mL of 0.10 M sodium sulfatesolution are mixed.
2. Two solutions containing 200 mL of 0.15 M strontium chloride and 150 mL of 0.09 Mpotassium chromate are mixed.
3. 225 mL of 0.5 M silver nitrate solution and 275 mL of 0.12 M lithium iodide solutionare mixed.
4. Two solutions containing 150 mL of 0.15 M lithium chloride and 150 mL of 0.10 Mlead (II) acetate are mixed.
5. A 50 mL solution of magnesium nitrate with a concentration of 0.20 M is combinedwith 100 mL of 0.15 M rubidium hydroxide.
6. 100 mL of 0.10 M ammonium phosphate solution is mixed with 200 mL of 0.12 Msilver nitrate solution.
7. A 150 mL solution of potassium hydroxide with a concentration of 0.40 M iscombined with 100 mL of 0.15 M aluminum acetate.
Two solutions containing 100 mL of 0.10 M sodium carbonate and 200 mL of 0.10 Maluminum chloride are mixed.
