CSEC Chemistry · January 2016 · Paper 2

47 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)1 markDefine the term 'rate of reaction'.
2. 1(a)(ii)2 marksState TWO factors, other than concentration, which affect the rate of a chemical reaction.
3. 1(b)(i)3 marksCalculate the concentration, in mol dm⁻³, of KIO₃ in Solution 1. [RAM: K = 39.1, I = 126.9, O = 16.0]
4. 1(b)(ii)2 marksThe final concentration of NaHSO₃ in all experiments was 0.0008 mol dm⁻³. Using the information provided in Table 1 on page 6, determine the concentration of NaHSO₃ in Solution 2.
5. 1(c)(i)3 marksFrom the stopwatches displayed in Figure 1 on page 7, record the times taken for the blue-black colour to appear in the appropriate spaces in Table 1. The time taken for Experiment 1 has already been recorded for you.
6. 1(c)(ii)3 marksCalculate the reciprocal times (1/time) and record them to 3 decimal places in the appropriate spaces in Table 1. One of the times has already been recorded for you.
7. 1(c)(iii)5 marksUsing the axes provided on page 8, plot a graph of concentration of KIO₃ versus reciprocal time for Experiments 1-5, and draw the best straight line through the points.
8. 1(d)2 marksBased on the graph drawn in (c) (iii) on page 8, what deduction can be made about the effect of concentration of aqueous KIO₃ on the rate of reaction?
9. 1(e)2 marksExperiment 6 was carried out using Solution X, which contained an unknown concentration of KIO₃. Using the reciprocal time calculated in Experiment 6, determine from your graph, the concentration of KIO₃ in this…
10. 1(f)(i)1 markState the responding variable.
11. 1(f)(ii)1 markState the controlled variable.
12. 2(a)1 markState ONE use of bleach in the laundering of clothing.
13. 2(b)(i)1 markDefine, in terms of oxidation state, the term 'oxidizing agent'.
14. 2(b)(ii)1 markDefine, in terms of oxidation state, the term 'oxidation'.
15. 2(c)3 marksDeduce the oxidation number of Cl in the formula, NaClO.
16. 2(d)(i)2 marksWhat is the change in oxidation number of Cl for the process?
17. 2(d)(ii)1 markIs this an oxidation or reduction process?
18. 2(d)(iii)2 marksDescribe a simple laboratory test for chlorine gas.
19. 2(e)4 marksDuring one stage of the reaction, H₂O₂(aq) is converted to H₂O(l). Use the changes in oxidation number to determine whether this is an oxidation or reduction process.
20. 3(a)(i)1 markState the name of Compound D.
21. 3(a)(ii)1 markIdentify the homologous series to which Compound D belongs.
22. 3(a)(iii)1 markState ONE chemical property of Compound D.
23. 3(b)(i)1 markState the name of Compound E.
24. 3(b)(ii)1 markIdentify the homologous series to which Compound E belongs.
25. 3(b)(iii)1 markWrite the general formula for this homologous series.
26. 3(c)(i)1 markState ONE physical property that is common to both Compounds F and G.
27. 3(c)(ii)1 markState which compound, F or G, will react with bromine in the dark.
28. 3(c)(iii)2 marksDraw the FULLY displayed structure of the product that is formed from the reaction in (c) (ii).
29. 3(d)(iv)1 markWill Compound F burn in air with a clear blue flame?
30. 3(d)(v)2 marksWrite a balanced chemical equation for the reaction that occurs when Compound F burns in air.
31. 3(d)(vi)2 marksState TWO properties of hydrocarbons that make them good fuels.
32. 4(a)(i)1 markDefine the term 'anion'.
33. 4(a)(ii)1 markWhat anions will be present in a sample of this electrolyte?
34. 4(a)(iii)4 marksDraw a clearly labelled line diagram to represent an electrolytic cell.
35. 4(b)5 marksCalculate the volume of hydrogen gas liberated at STP, if a current of 965 A is passed through the circuit for 1 hour. (Q = I × t, F = 96 500 C mol⁻¹. At STP, 1 mol of gas occupies 22.4 L)
36. 4(c)4 marksRemi also wants to purify an impure nickel sample by electrolysis. Suggest how he could modify the line diagram drawn in (a) (iii) on page 16 in order to achieve this, and state ONE observation that would be expected.
37. 5(a)1 markState ONE natural source of hydrocarbons.
38. 5(b)4 marksList TWO other fractions that can be obtained and state ONE use of EACH fraction.
39. 5(c)(i)1 markDefine the term 'cracking'.
40. 5(c)(ii)2 marksHow does catalytic cracking differ from thermal cracking?
41. 5(d)(i)5 marksWrite an equation, using FULLY displayed structures, which summarizes the expected reactions in EACH case. Identify any products formed.
42. 5(d)(ii)2 marksWrite a balanced chemical equation for the complete combustion of pentane.
43. 6(a)1 markIdentify TWO reagents that are necessary for the laboratory production of ammonia.
44. 6(b)3 marksExplain why concentrated sulfuric acid is not used. Include in your answer a balanced chemical equation.
45. 6(c)(i)2 marksWhat TWO factors should be considered when choosing an appropriate method for the collection of gases in the laboratory?
46. 6(c)(ii)5 marksIdentify ONE of the three methods that is best suited for the collection of ammonia gas in the laboratory. Explain why EACH of the other two methods would NOT have been appropriate.
47. 6(d)4 marksHence, draw a labelled diagram of the apparatus which could be used for the preparation of dry ammonia in the laboratory. Be sure to identify in your diagram where the reagents are placed, where the ammonia is dried,…