Reg. No. 200710217Z Page16 Advo Education Group Pte Ltd Foundation Question for Inorganic Chemistry Periodicity 1 . N2003/II/1(a)(b)(ii) [The use of the Data Booklet is relevant to this question.] (a ) Complete these sketches for elements of the third period to show how each property, (i) melting point, (ii) electrical conductivity, (iii) ionic radius, changes along the period and briefly explain the shapes of each of your sketches. (b ) Write an equation for the reaction of each of the following oxides with aqueous sodium hydroxide. (i) sulfur dioxide (ii) aluminium oxide 2 . The melting points of three chlorides are given below. Compound melting point / o C magnesium chloride 701 aluminium chloride 178 A is Easy with ADVO! Tel: (65) 6251 3359 / 8233 2753 www.advoedu.com 1 Goldhill Plaza #02-43 Singapore 308899
Transcript
Reg. No. 200710217Z
Page
16
Advo Education Group Pte Ltd
Foundation Question for Inorganic Chemistry Periodicity
1. N2003/II/1(a)(b)(ii) [The use of the Data Booklet is relevant to this question.] (a)
Complete these sketches for elements of the third period to show how each property,(i) melting point, (ii) electrical conductivity, (iii) ionic radius, changes along the period and briefly explain the shapes of each of your sketches.
(b)
Write an equation for the reaction of each of the following oxides with aqueous sodium hydroxide. (i) sulfur dioxide (ii) aluminium oxide
2. The melting points of three chlorides are given below.
Compound melting point / oC
magnesium chloride 701aluminium chloride 178
silicon chloride 70(a)
Briefly relate these melting points to the structure of, and bonding in, each of these chlorides.
[3]
(b Describe the reaction, if any, of each of these chlorides with water, A is Easy with ADVO!
) stating the approximate pH of any solution formed, and writing a balanced equation for any reaction that takes place. [5
]2.
(c)
Using your answer in (b) and data from the Data Booklet, suggest thepH of 1.0 mol dm−3 solution of FeCl3. Explain your answer. [2
][Total : 10]
3. (a)
Describe what you see when magnesium, phosphorus and sulfur are separately burned in air or oxygen. Write an equation for the reactions that occur.
[4]
(b) The oxides of magnesium, aluminium and phosphorus differ in their reactions with water. Describe these reactions, relating them to the structure and bonding in each oxide. Write equations where appropriate.
[5]
(c) Describe the effect of the resulting solutions in (b) on Universal Indicator solution.
[1]
(d) Write balanced equations, where applicable, to show how each oxide of magnesium, aluminium and phosphorus reacts with (i)
NaOH(aq) (ii)
HCl(aq) [4]
[Total : 14]
4. N2007/ III /2(b)(c) - ModifiedThe oxides MgO, Al2O3 and SiO2 are all used as refractory materials due to their high melting points. The last two are major constituents of gemstones, such as rubies, sapphires and amethysts.(a) If a sample of one of the oxides was provided as a white powder,
describe the reactions you could carry out on the powder to determine which of the three oxides it was. [3
](b)
Compound sodium chloride
phosphorus pentachloride
pH of resulting solution upon
addition of compound to water
7 1
Explain the above observations, and why these two chlorides differ in their reaction with water.
5. N2008/ III /4(a)(b)(c)(d) When dry chlorine is passed over heated aluminium foil in a hard glass tube, a vapour is produced which condenses to a yellow-white solid in the cooler parts of the tubes. At low temperatures the vapour has the empirical formula AlCl3, and Mr of 267.(a) Suggest the molecular formula of the vapour, and draw a dot-and-
cross diagram to describe its bonding. [2]
The yellow-white solid reacts with water in two separate ways.When a few drops of water are added to the solid, steamy white fumes are evolved and a white solid remains, which is insoluble in water.When a large amount of water is added to the solid, a clear, weakly acidic solution results.(b) Write equations, including state symbols, for these two reactions and
explain the observations. [4]
(c) Describe and explain what you would see when a sample of Na2O (s) is added to a solution of litmus in water. Write an equation for the reaction that occurs.
[2]
(d) When magnesium is burned in air, a mixture of the ionic solids magnesium oxide and magnesium nitride, Mg3N2, is formed. Adding water to Mg3N2 produces an alkaline gas and a white insoluble solid.(i) Use a dot-and-cross diagram to describe the bonding in Mg3N2.(ii) Suggest an equation for the reaction between Mg3N2 and water,
and use it to calculate the mass of white insoluble solid that would be formed from 2.0 g of Mg3N2.
6. N2006/ I /13 The labels had become detached from four bottles in the laboratory. A student realised that the contents of one of them could easily be identified because, on addition of water it would not give fumes of hydrogen chloride.Which did not give the acid fumes?
A Al2Cl6 C PCl5B MgCl2 D SiCl4
7. N2007/ I /15 What is not a trend from left to right across the elements of the third period of the Periodic Table?
A The radii of the atoms decrease.B The oxides of the elements change from basic to acidic.C The melting points of the elements decrease steadily.D The compounds of the elements change from ionic to covalent.
8. N2008/ I /14 The chloride of an element R of the third period is a liquid which has a boiling point of 76 °C and fumes in air.After mixing 0.010 mol of the chloride with water, the resulting solution required 100 cm3 of 0.30 mol dm−3 silver nitrate for complete precipitation of the chloride ion.To which Group of the Periodic Table does R belong?
A II C IVB III D V
9. N2010/ I /14 Use of the Data Booklet is relevant to this question.Natual water in reservoirs often contains very finely divided solid particles of
between 1 and 100 nm in diameter which have negative charges on their surface.
One stage in purifying the water consists of adding salt solutions containinghigh charge-density cations which neutralise the negative charges and cause the solid particles to join together and settle out.Which compound, in aqueous solution, would be the most effective in precipitating finely divided solid particles?
A MgCl2 C FeCl3B AlCl3 D SiCl4
10. N2006/I/14 11.
N2010/I/15
The bar chart shows the melting points of a series of consecutive elements arranged in order of increasing atomic number. The elements sodium to chlorine form part of these series.Which bar represents sodium?
Phosphorus is an element in the third period, Na to Ar, of the Periodic Table.What is true for phosphorus and none of the other elements in this period?A Phosphorus has the highest
melting point of the elements in this period.
B Phosphorus is the only element in this period which forms two acidic oxides.
C Phosphorus is the only element in this period with exactly four atoms in its molecule.
D Phosphorus is the only element in this period whose chlorides react with water to form acidic solutions.
Group II
1. J93/P1/6(a) modifiedFully describe the reactions, with appropriate equations, of the Group II metals, calcium and barium, with
2. J98/P1/Q4 modified(a) The melting points of Group II oxides
are given in the table on the right.Oxide MgO CaO SrO BaOMelting point / °C
2852
2614
2430
1918
(i) With reference to the given data, explain the trend in the melting point of Group II oxides.
(ii) By stating one of these oxides clearly, suggest and explain a use based on its melting point. [3]
(b) Dolomite is a mineral with the formula CaMg(CO3)2. A 1.000 g sample of dolomite produced 0.450 g of carbon dioxide when treated with an excess of hydrochloric acid.(i) Construct a balanced equation for the reaction involved.(ii) Calculate the percentage purity of the dolomite sample. [3]
3. N01/P2/Q3(e) modifiedLime can be obtained by thermal decomposition of solid calcium carbonate.(a) Write an equation for the thermal decomposition of calcium carbonate. [1](b) Calcium carbonate decomposes at a lower temperature than barium
carbonate. Explain. [2](c) Explain why lime is used in agriculture [1]
4. N00/P1/Q5 modified(a) Describe and explain the variation, down the group, on the ease of
thermal decomposition of the Group II metal nitrates. Write an equation for the reaction that takes place. [3]
(b) When water is added to the solid residue, after barium nitrate has been heated, an alkaline solution is produced. The addition of sulfuric acid to this solution produces a white precipitate. Identify the products of these two reactions, and write equations for the reactions that occur. [4]
(c) When the procedure described in (b) is repeated using the solid remaining after magnesium nitrate has been heated, several differences are observed. Describe clearly these differences. [3]
(d) A 4.50 g sample of a carbonate of a Group II metal (known to be [3]A is Easy with ADVO!
either calcium or strontium) lost 1.34 g in mass when heated strongly.Identify the metal, showing clearly your working. Thus, construct an equation to illustrate the reaction that occurs.
5. Magnesium reacts with nitrogen only at very high temperature, producing a yellow solid Z. Z contains 72% of magnesium, by mass.(a)
Suggest why a high temperature is required for this reaction.[1]
(b)
Determine the empirical formula of Z.[1]
(c) When water is added to the yellow solid Z, a white suspension forms and ammonia is liberated. Identify the white suspension and write an equation for the action of water on Z. [2]
MCQ:
6. Which of the following decreases down Group II?
A reactivity of the elementsB magnitude of ∆Hhyd of the ionsC thermal stability of the carbonatesD pH of the oxides in water
7. Radium is the last element in Group II in the Periodic Table. Which of the following is not true for radium?
A Its compounds conduct electricity when molten.B Its oxide forms an alkaline solution with water.C It reacts with water to release hydrogen gas.D It is the least reactive element in Group II.
8. On strong heating, CaSO4 decomposes into CaO and SO3. Calcium carbonate, CaCO3, decomposes at a lower temperature than calcium sulfate, CaSO4.Which factor best explains the greater thermal stability of CaSO4?
A CO2 is a smaller molecule than SO3.B CaCO3 has a higher lattice energy than CaSO4.C CO32– ions are more easily polarised than SO42–.D The charge density of CO32– is greater than that of SO42–.
9. TYS pg 99 Q1 N03/P1/34 modifiedA is Easy with ADVO!
1 It reacts with cold water2 It is a product when calcium nitrate is heated.3 It is used to treat soil acidity
10.
N2001/P3/13Two reaction routes for a Group II metal, M, is given below:
Which of the following sets contains three different compounds?A H, J, Z B H, K, YC J, X, Z D K, X, Y
Group VII
1. N93/P1/Q7(a) How do the chloride, bromide and iodide ions differ in their reactions with
(i) silver nitrate, followed by aqueous ammonia,
(ii) concentrated sulfuric acid?
In each case, suggest the products of the reaction and write the equations, where appropriate. [8](b) What explanations can you offer for the differences in their reactions?
[3]
2. J89/P1/Q5 State what you would observe in each of the following experiments. Explain these observations with the aid of the Data Booklet where appropriate.
(a) Solid iodine is shaken with aqueous potassium iodide; aqueous sodium thiosulfate is then added.
(b) Aqueous iron(III) sulfate is added to aqueous potassium iodide and a few drops of starch indicator are then added.
(c) Aqueous chlorine is added to aqueous iron(II) sulfate and aqueous sodium hydroxide is then added.
(d) Chlorine is passed into aqueous sodium hydroxide at room temperature and the mixture is then [3×4]
3. N06/P3/Q5aWhen sparked with hydrogen, chlorine reacts explosively and completely, while iodine reacts slowly and reaches equilibrium.(i) Write an equation for the reaction between chlorine and hydrogen.
(ii) Describe and explain the trend observed in the reactions of the elements chlorine, bromine and iodine with hydrogen.
(iii) When sodium thiosulfate is reacted separately with chlorine and iodine, different products are formed.
Use the following data, and data from the Data Booklet, to suggest an explanation for this difference.
[5]
4. N03/P3/Q5(a) Describe and explain how the thermal stability of the hydrogen halides varies down Group VII. [3](b) Describe, including an equation for the reaction, what you would see if chlorine water is added to
aqueous sodium bromide.[2]
(c) When chlorine is bubbled through an aqueous solution containing sodium hydroxide and sodium bromide, bromide ions are oxidised to a bromide-containing oxyanion. Careful addition of aqueous silver nitrate to the resulting solution precipitates 4.31 g of white solid. When this precipitate is filtered off and more silver nitrate solution added, 1.18 g of cream solid is produced. The cream solid had the following composition by mass :
Ag, 45.8% ; Br, 33.9% ; O, 20.3%
(i) Determine the empirical formula of the cream solid
(ii) Calculate the number of mole of cream solid and white solid formed.
(iii) Hence, construct a balanced equation for the reaction between chlorine, sodium bromide and sodium hydroxide. [5]
MCQ:
1.
J95/P4/Q15
Which of the following graphs correctly describes a trend found in the halogen A is Easy with ADVO!
Which product(s) is/are obtained when chlorine is bubbled into hot concentrated sodium hydroxide?A NaClO onlyB NaClO3 onlyC NaCl and NaClOD NaCl and NaClO3
3.
N07/P1/Q16
The ash from burnt seaweed contains chlorides and iodides of some Group I and Group II elements. Some seaweed ash was treated with concentrated sulfuric acid and the resulting fumes passed first through a cold tube and lastly bubbled through aqueous silver nitrate.
What would be observed during the experiment?
Inside the cold tube
With aqueous silver nitrate
A Black deposit White precipitateB Black deposit Yellow precipitateC No deposit White precipitateD No deposit Yellow precipitate
The table shows the results of experiments in which the halogens X2, Y2 and Z2 were added to separate aqueous solutions containing X–, Y–
and Z– ions.
Which of the following set contains the ions X–, Y– and Z– in order of their decreasing strength as a reducing agent?
Strongest WeakestA X– Y– Z–
B X– Z– Y–
C Y– Z– X–
D Z– X– Y–
5. A solution of sodium chlorate(I), commonly used as bleach, can be made from the electrolysis of brine (concentrated aqueous sodium chloride) using a diaphragm cell as shown.
By mixing the contents of which compartment can a solution of sodium chlorate(I) be made?A P and R C Q and RB P and S D Q and S
6.
N11/P1/Q15
HCl is stable to heat, but HI decomposes into its elements when heated. What is responsible for this difference?A HI is a stronger reducing agent than HCl.B HI is more volatile than HCl.C The H─I bond is weaker than the H─Cl bond.D The I─I bond is weaker than the Cl─Cl bond.
Which statement(s) about the trends in the properties of the halogens is/are correct?1 The electronegativity decreases on descending the group.2 The volatility decreases on descending the group.3 Their reactivity as oxidising agents decreases on descending the group.
8. J04/P1/Q36When a hot glass rod is inserted into a gas jar of hydrogen iodide, an immediate reaction takes place as the hydrogen iodide decomposes. Which of the following is/are correct statement(s) about this reaction?
1 Hydrogen iodide is purple coloured.2 The hot rod provides the activation energy.3 One of the products is a solid.
9. N01/P3/Q36The chemical behaviour of the cyanide ion, CN–, closely resembles that of Cl –. Which of the following properties can be expected of compounds containing cyanide?
1 AgCN is insoluble in water but soluble in aqueous ammonia.2 HCN dissolves in water, ionises and forms an acidic solution.3 NaCN reacts with concentrated sulfuric acid to produce HCN gas.
10.
KClO3, which is used as an oxidant in fireworks and safety matches, is an ionic compound.Which of the following statements about KClO3 are correct?1 KClO3 may be made by reacting Cl2 with hot KOH(aq).2 The shape of ClO3– ion is tetrahedral. 3 The oxidation number of Cl in KClO3 is 7.
1. (a) What do you understand by the terms transition element, ligand and complex ion?
(b) Iron is an important component of several biological molecules, especially haemoglobin.(i) What is the function of haemoglobin in the body, and how does
it carry out this function?(ii) Carbon monoxide acts as a poison through its interaction with
haemoglobin. Describe this interaction and explain why carbon monoxide is a poison.
(c) A patient suffering from carbon monoxide poisoning can be treated by being given pure oxygen to breathe. Suggest a reason why this treatment is effective.
2. N09(Int’l)/P4/Q3b, J96/P4/Q22b modified(a) One major difference between the properties of compounds of the
transition elements and those of other compounds is that the compounds of the transition elements are often coloured.
The following graph shows the absorption spectra of two complexes containing copper.
(i) State the colours of the [Cu(H2O)6]2+ and [Cu(NH3)4(H2O)2]2+
complex ions.*(ii)
The spectra show that the peak in the curve for [Cu(H2O)6]2+
complex is at a longer wavelength than is the peak in the curve for [Cu(NH3)4(H2O)2]2+ complex.
What deduction can be made from this fact about the size of A is Easy with ADVO!
the d-orbital splitting in the two complexes? [3](b) The following table lists some values of equilibrium constants,
also known as stability constants, Kstab, for the following reaction.[M(H2O)6]m+ + nL [M(H2O)6nLn] (mn)+ + nH2O
(where m and n are whole numbers)M m+ L n Kstab valueFe3+ SCN 1 9 x 102
Fe3+ CN 6 1 x 1031
Co3+ CN 6 1 x 1064
(i) Rewrite the above equation for the case of M m+ = Fe3+ and L = CN. Write the expression for the equilibrium constant Kstab, and state its units.
(ii) What does a large Kstab value indicate about the position of the above equilibrium and hence, the ease of formation of the complex ion?
(iii) Use the data given in the table to predict what would be the predominant complex formed when:1: a solution containing equal concentrations of both SCN
and CN ions was added to a solution containing Fe3+
(aq) ions;2: a solution containing equal concentrations of Fe3+(aq)
and Co3+(aq) ions was added to a solution containing CN ions.
[7]
3. Use of Data Booklet is relevant to this question.(a) Explain why so many transition element complexes are coloured. [3](b) Predict and explain the change in colour caused by adding the
following substances to separate portions of aqueous iron(III) chloride: (i) aqueous potassium thiocyanate, KSCN;(ii) powdered zinc. [4]
4. Use of Data Booklet is relevant to this question.This question is about iron and its compounds.(a) Many transition metals and their compounds are useful catalysts.
An aqueous solution of Fe2+ is able to catalyse the reaction between iodide ions and peroxodisulfate, S2O82, ions whereas Ca2+
cannot.(i) Why is it necessary to catalyse the reaction between iodide
ions and peroxodisulfate ions?(ii Why is Fe2+ and not Ca2+ suitable as catalyst?
Explain, with the aid of equations, how Fe2+ is able to catalyse the above reaction.
(iv)
Give an example of a reaction in which iron act as a heterogeneous catalyst. Write a balanced equation for the reaction it catalyses and explain how it works as a catalyst. [8]
4. (b) When iodide ions I are added to Fe3+, a brown solution is obtained. However, when the same process is repeated in the presence of CN ions, no brown solution is observed. Explain the difference in the observations of the experiments. In your answer, include balanced equations for reactions that occur. [3]
5. (a) In an experiment, the student prepared two complexes with the general formula CrCl3.6H2O. Upon adding AgNO3(aq) to the aqueous solutions of P and Q, he noted the following.
Solution No of mole of AgCl precipitated per mole of solution
P 1Q 3
(i) Based on these observations, deduce the structural formulae of the cations in solutions P and Q. Explain your answer.
(ii) Given that the cation in solution P is non-polar, draw its structural formula.
[3]
(b) (i) State a reason why Cr(VI) exists as CrO42(aq) ions and not Cr6+(aq) ions.
(ii) Write an equation to show the effect of acid on CrO42(aq) ions. Is this a redox reaction? [3]
6. N01/P4/Q22 modifiedThis question is about copper and its compounds.(a) Briefly explain why complexes of Cu(II) are coloured whereas
complexes of Cu(I) are colourless, despite the fact that the d-orbitals are split into two energy levels in both series of complexes.
[2]
(b) White copper(I) sulfate undergoes disproportionation when added to water to form a blue solution and a pink solid.Explain the above observation when copper(I) sulfate is added to water. Write a balanced equation for the reaction occurred. [2]
A contains complex ions of copper and chlorine. When CuCl2(aq) is converted to A, one mole of CuCl2 reacts exactly with two moles of HCl and no other compound is formed. (i) Identify B and state the role of ammonia in the reaction
forming B.(ii) Identify A and C. Explain, in terms of ligand exchange, how
A and C are formed. In your answer, include equations for the reactions that occurred.
[8]
*(d) When copper metal is added to a solution of copper(II) chloride in concentrated hydrochloric acid, a colourless solution, D, is formed. D contains complex ions that are composed of only copper and chlorine in the ratio of 1:2. Suggest the formula of the species responsible for the colourless solution, D.
[1]
MCQ:
1. N93/P4/Q20Iron has a proton (atomic) number of 26.What is the electronic configuration of the iron cation which can form the complex ion [Fe(CN)6]4−? [[Ar] ≡ 1s2 2s2 2p6 3s2 3p6]
A [Ar] 3d34s2 C [Ar] 3d64s0
B [Ar] 3d44s2 D [Ar] 3d64s2
2. N04/P1/Q19 Which species does not act as a ligand in the formation of complexes?A CH3NH2
B ClC NH4+
D OH
3. J97/P3/Q16Which of the following ions contains five unpaired d-electrons?
4. N01/P3/Q17 Which statement concerning the transition metals is correct?
A They are the only metals of which the anhydrous chlorides have covalent bonds.
B They are the only metals which give coloured ions in aqueous solution.
C They are the only metals which have more than one valency (oxidation state).
D They are the only metals with a complete 4s orbital in their atoms.
A B C D1, 2 and 3 are
correct1 and 2 only are
correct2 and 3 only are
correct1 only are correct
5. In an experiment, when NaOH(aq) is added to Cr(NO3)3(aq), a grey-green precipitate is formed and the precipitate dissolves in excess NaOH(aq) to give a dark green solution.Which of the following processes occured in this experiment? 1 Reduction of Cr3+ ions2 Precipitation of Cr(OH)33 Formation of dative bonds
6. When crystalline potassium chromate(VI) was dissolved in water, a yellow solution Q was formed. The addition of dilute sulfuric acid to Q gave an orange solution R. When hydrogen sulfide was bubbled through solution R, the solution changed colour and gave a solution T, with a yellow solid.Which process does not occur in this sequence?1 Ligand exchange reaction2 Acid-base reaction3 Redox reaction
