CAPE Chemistry Unit 2 · 2006 · Paper 2

61 questions and parts from this paper. Open one to see it in full, then practise it on Quelpr and get it marked against the mark scheme.

1. 1(a)(i)2 marksPredict quantitatively the effect on the rate of reaction when the concentration of H₂(g) is doubled, and give a reason.
2. 1(a)(ii)2 marksPredict quantitatively the effect on the rate of reaction when the concentration of NO(g) is halved, and give a reason.
3. 1(a)(iii)1 markPredict quantitatively the effect on the rate of reaction when the concentrations of H₂(g) and NO(g) are both tripled.
4. 1(b)(i)2 marksSketch a suitable graph representing the data collected (volume of products formed versus time).
5. 1(b)(ii)1 markApart from volume measurement, state ONE other method of monitoring the rate of this reaction.
6. 1(b)(iii)2 marksSuggest TWO precautions that should be taken when performing the experiment in (b)(ii).
7. 2(a)(i)2 marksWrite a balanced equation for the reaction occurring when chlorine is bubbled through cold aqueous dilute sodium hydroxide.
8. 2(a)(ii)1 markCalculate the oxidation number of chlorine in NH₄ClO₄.
9. 2(b)(i)1 markState the observation when aqueous chlorine is added to aqueous potassium bromide and the mixture is shaken.
10. 2(b)(ii)2 marksState the observation when aqueous silver nitrate is added to a sample of aqueous sodium chloride followed by ammonia solution.
11. 2(b)(iii)1 markState the observation when warm concentrated sulphuric acid is added to solid potassium iodide.
12. 2(c)2 marksWrite an ionic equation for the reaction occurring in (b)(i).
13. 2(d)1 markWhat precaution must be taken when performing the reaction in (b)(iii) in the laboratory?
14. 3(a)2 marksIdentify source A and process I used to obtain nitrogen gas.
15. 3(b)(i)1 markSuggest another condition required at process II which is used to yield hydrogen gas from CH₄ and H₂O.
16. 3(b)(ii)2 marksWrite a balanced equation for the reaction at process II.
17. 3(c)2 marksIdentify the condition at III that minimizes the time taken to produce a batch of ammonia from the starting materials, and give a reason.
18. 3(d)2 marksUnder what conditions would ammonia be held in the storage cylinders?
19. 3(e)1 markDescribe a simple laboratory test that could be carried out at point X to test for a leak in a storage cylinder.
20. 4(a)(i)2 marksState Le Chatelier's principle.
21. 4(a)(ii)2 marksGive TWO characteristic features of a system in dynamic equilibrium.
22. 4(a)(iii)1 markWrite an expression for the equilibrium constant, K_p, for the equilibrium system described.
23. 4(a)(iv)2 marksThe equilibrium constant, K_p, for this reaction is 4.0 × 10¹⁹ Pa⁻¹ at 25 °C. Use the value of K_p to comment on the position of equilibrium at 25 °C and the relative equilibrium concentration of reactants and products.
24. 4(b)(i)3 marksUsing Le Chatelier's principle, predict and explain how the position of equilibrium and the concentration of reactants and products are affected when the temperature is increased while pressure is kept constant.
25. 4(b)(ii)3 marksUsing Le Chatelier's principle, predict and explain how the position of equilibrium and the concentration of reactants and products are affected when the pressure is increased while temperature is kept constant.
26. 4(b)(iii)2 marksUsing Le Chatelier's principle, predict and explain how the position of equilibrium and the concentration of reactants and products are affected by using a catalyst.
27. 4(c)5 marksWhen a 2:1 mixture of SO₂(g) and O₂(g) at a total initial pressure of 5 atm is passed over a catalyst at 425 °C, the partial pressure of SO₃(g) at equilibrium is found to be 3 atm. Calculate the value of K_p.
28. 5(a)2 marksDefine the term 'buffer solution'.
29. 5(b)(i)1 markSuggest a reason for adding a buffer to the pool.
30. 5(b)(ii)2 marksUse the equation HCO₃⁻(aq) + H₂O(l) ⇌ H₃O⁺(aq) + CO₃²⁻(aq) to explain how the aqueous hydrogen carbonate ion acts as a buffer.
31. 5(c)(i)3 marksExplain how the molecular structure of amino acids relates to their function as buffers in human blood.
32. 5(c)(ii)1 markState ONE industry in which buffers are used.
33. 5(d)(i)2 marksCalculate the concentration of the sodium ethanoate solution in mol dm⁻³.
34. 5(d)(ii)5 marksK_a for ethanoic acid is equal to 1.8 × 10⁻⁵ mol dm⁻³. Write the expression for K_a and use it to calculate the pH of the buffer solution. State any assumptions made in the calculation.
35. 5(e)(i)2 marksFind the new concentrations of sodium ethanoate and ethanoic acid.
36. 5(e)(ii)2 marksComment on the pH of the new solution and explain your answer.
37. 6(a)(i)6 marksExplain the trend in the bonding and acid/base character of the Group IV oxides in the +2 state.
38. 6(a)(ii)2 marksExplain the trend in the behaviour of the Group IV tetrachlorides on reacting with water.
39. 6(b)(i)6 marksA brown solid, J, heated with concentrated sulphuric acid reacts to give a white solid, K, and a colourless, odourless gas, L, which relights a glowing splint. J reacts with aqueous manganese(II) nitrate in the presence…
40. 6(b)(ii)4 marksWhen acidified potassium chromate(VI) is added to an aqueous chloride, P, it changes from orange to green. P can also be used to change nitrobenzene (C₆H₅NO₂) to phenylamine (C₆H₅NH₂). Identify P and explain its role in…
41. 6(b)(iii)2 marksSuggest what would be observed when aqueous P reacts with aqueous iron(III) chloride. Explain your answer.
42. 7(a)(i)5 marksSuggest the structure for EACH of substances A to E.
43. 7(a)(ii)5 marksA to E may be a Period 3 element or its oxide or chloride. Suggest the identity of the substances, A to E.
44. 7(b)(i)8 marksDescribe the reaction of EACH of the following substances with water: a) Sodium b) Magnesium c) Chlorine
45. 7(b)(ii)2 marksWrite an equation for ONE of the reactions described in (b)(i).
46. 8(a)4 marksGive ONE use for EACH of PVC and PET and suggest why these polymers do not respond to natural degradative processes.
47. 8(b)(i)1 markSuggest the meaning of the term 'depolymerization'.
48. 8(b)(ii)5 marksState TWO chemicals that could be used in the depolymerization of PET and explain the chemical process occurring.
49. 8(c)(i)1 markWhat would be a suitable solvent for this process?
50. 8(c)(ii)1 markSuggest a reason for the use of fine chips.
51. 8(c)(iii)2 marksGive TWO safety precautions that should be enforced during this recycling process.
52. 8(c)(iv)1 markSuggest a use or property of any clothing produced from these recycled fibres.
53. 8(d)5 marksDiscuss the advantages and disadvantages of disposing of PVC material via incineration.
54. 9(a)(i)3 marksBriefly describe the principles involved in fractional distillation.
55. 9(a)(ii)2 marksBriefly describe the principles involved in cracking.
56. 9(b)2 marksGive a balanced equation to illustrate cracking.
57. 9(c)1 markExplain the importance of EITHER fractional distillation OR cracking.
58. 9(d)3 marksSuggest ONE adverse effect associated with the extraction of crude oil and comment on the environmental problems that result.
59. 9(e)(i)2 marksState TWO reasons why the use of leaded petrol is hazardous to human health.
60. 9(e)(ii)5 marksAccount for the presence of carbon monoxide and nitrogen oxides in the exhaust gases of cars. Write a balanced equation for the formation of ONE oxide of nitrogen.
61. 9(e)(iii)2 marksSuggest TWO means by which the amount of carbon monoxide and nitrogen oxides in vehicle exhaust fumes may be reduced to minimize pollution levels.