CAPE Chemistry Unit 1 · 2006 · Paper 2

62 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 markCalculate the mass of carbon in 3.52 g of carbon dioxide
2. 1(a)(ii)1 markCalculate the mass of hydrogen in 1.62 g of water.
3. 1(b)2 marksUse the answers obtained in (a) (i) and (a) (ii) to calculate the empirical formula of A.
4. 1(c)2 marksThe molar mass of A is 114 g mol-¹. Calculate its molecular formula.
5. 1(d)(i)2 marksDescribe simple tests that could be used to confirm that the products of the combustion of A are water and carbon dioxide (You must include in your answer the reagent used and the observation obtained for EACH test).…
6. 1(d)(ii)2 marksDescribe simple tests that could be used to confirm that the products of the combustion of A are water and carbon dioxide (You must include in your answer the reagent used and the observation obtained for EACH test).…
7. 2(a)(i)4 marksComplete Table 1, row (i) for the observation when an alkaline solution of silver nitrate is added to a few cm³ of X and the mixture is warmed, given the inference is Aldehyde.
8. 2(a)(ii)4 marksComplete Table 1, row (ii) for the observation when iodine and X are warmed with some NaOH in a test tube, given the inference is Methylketone.
9. 2(a)(iii)4 marksComplete Table 1, row (iii) for the observation when X is added to a few cm³ of bromine in tetrachloromethane, given the inference is Alkene.
10. 2(a)(iv)4 marksComplete Table 1, row (iv) for the inference when X is added to dilute HCl and white crystals are produced.
11. 2(a)(v)1 markSuggest a value for the pH of a solution of X.
12. 2(a)(vi)1 markThe mass spectrum of X reveals that it has a RMM of 203. A prominent peak is also observed in the mass spectrum at m/z 77. Use this information and the results of your chemical analysis as recorded in Table 1 above to…
13. 2(b)(i)3 marksComplete Table 2, row (i) for the inference when Acidified KMnO4 is added to a few cm³ of Y, and the mixture is warmed, and the observation is colour changes from purple to colourless.
14. 2(b)(ii)3 marksComplete Table 2, row (ii) for the test when the observation is white precipitate produced, and the inference is Phenol present.
15. 2(b)(iii)3 marksComplete Table 2, row (iii) for the test when the observation is gas evolves which forms white fumes with NH3(g), and the inference is Carboxylic acid group.
16. 2(b)(iv)1 markThe molecular formula for Y is found to be C9H10O4. Suggest a structural formula for Y.
17. 3(a)3 marksIdentify EACH of the processes 1, 2 and 3 in Figure 1.
18. 3(b)(i)3 marksSuggest the name of Solvent A and explain why the solvent suggested is suitable.
19. 3(b)(ii)1 markDescribe Mixture B
20. 3(c)(i)1 markSuggest a suitable piece of equipment which could be used to obtain the extracted product
21. 3(c)(ii)1 markSuggest a suitable piece of equipment which could be used to obtain the dry crystals.
22. 3(d)1 markMixture B shows some discolouration and an additional step is required before Process 2. Name the purifying agent necessary in this step.
23. 4(a)(i)4 marksDescribe the features of a chemical system in a state of dynamic equilibrium.
24. 4(a)(ii)1 markDefine the term 'equilibrium constant'.
25. 4(a)(iii)5 marksDescribe and explain, with reference to changes in colour, the observations made when hydrogen gas is reacted with iodine gas at constant temperature until equilibrium is achieved.
26. 4(a)(iv)a)3 marksUse the information in Table 3 and the equation in (a) (iii) above to calculate the number of moles of hydrogen reacting.
27. 4(a)(iv)b)3 marksComplete the table by inserting the equilibrium concentrations of I2 and HI.
28. 4(a)(v)2 marksWrite an equation for Kp for the reaction in (iii) above.
29. 4(b)(i)a)3 marksWrite an expression for EACH of the following terms: Ka
30. 4(b)(i)b)3 marksWrite an expression for EACH of the following terms: pKa
31. 4(b)(i)c)3 marksWrite an expression for EACH of the following terms: pH
32. 4(b)(ii)2 marksGiven that Ka for acid HP is 3.0 x 10-5 mol dm-³, predict the relative size of Ka for a stronger acid HQ. Explain your reasoning.
33. 5(a)(i)2 marksExplain EACH of the terms 'oxidation' and 'reduction', in terms of loss and or gain of electrons
34. 5(a)(ii)2 marksExplain EACH of the terms 'oxidation' and 'reduction', in terms of change in oxidation number.
35. 5(b)(i)2 marksUse the appropriate half equations (from those above) to write a balanced equation to show the reaction between hydrogen peroxide and chloric (I) (hypochlorous) acid.
36. 5(b)(ii)6 marksBy making reference to the change in oxidation numbers of the elements in both the hydrogen peroxide AND the chloric (I) acid, determine which reactant is reduced and which is oxidised.
37. 5(c)(i)3 marksState what type of chemical reaction occurs and write an ionic equation for the reaction.
38. 5(c)(ii)4 marksWhich element has the greater reducing ability? Explain your answer, using a suitable half equation.
39. 5(c)(iii)1 markTin shows no reaction with solutions of EITHER iron or nickel salts. Place the elements, tin, iron and nickel in order of INCREASING reducing ability.
40. 6(a)(i)6 marksDescribe EACH of the following terms, using appropriate examples: Homolytic bond fission
41. 6(a)(ii)6 marksDescribe EACH of the following terms, using appropriate examples: Inductive effect
42. 6(b)(i)4 marksState TWO types of reaction mechanisms which citral will undergo, identifying the functional group involved in EACH case.
43. 6(b)(ii)8 marksWith the use of simple molecules containing the functional groups identified in (b) (i), explain the steps involved in EACH of the mechanisms mentioned in (b) (i).
44. 6(c)2 marksIdentify the mechanism and draw the product of this reaction.
45. 7(a)(i)4 marksFor the reaction sequence given above, state the reagents and conditions needed for Reactions I and II.
46. 7(a)(ii)2 marksIdentify ONE OTHER product that could be obtained in Reaction I by changing the conditions. State the condition(s) needed.
47. 7(b)(i)8 marksExplain the differences in basic character of A, ammonia and amphetamine. In your explanation make reference to the molecular features of each molecule. State the order of INCREASING basic character of the three…
48. 7(b)(ii)1 markWrite an equation to show the basic nature of any ONE of the above substances.
49. 7(b)(iii)2 marksThe pKa of A is 9.62. Suggest how the pKa of amphetamine and ammonia should vary relative to that of A.
50. 7(c)(i)2 marksPredict pH values for difluoroethanoic acid and dibromoethanoic acid.
51. 7(c)(ii)1 markWould benzoic acid be a stronger or weaker acid than ethanoic acid?
52. 8(a)(i)2 marksCalculate the mean of ΔHsoln NaCl from the data.
53. 8(a)(ii)3 marksComment on the precision and accuracy of the results.
54. 8(a)(iii)3 marksCalculate the standard deviation of the data and explain the significance of the value.
55. 8(b)(i)6 marksDiscuss whether each instrument is appropriate for the measurement taken and suggest possible alternatives where necessary.
56. 8(b)(ii)4 marksGive TWO reasons for calibrating an instrument such as a thermometer and suggest TWO steps involved.
57. 8(c)2 marksUse the calibration curve in Figure 2 to determine the density of a block of metal that displaces a volume of 4.0 cm³.
58. 9(a)3 marksState which type of distillation is BEST suited for separating EACH compound from a mixture of the compound in water.
59. 9(b)(i)5 marksConstruct the b.p / composition curve for the mixture of Z in water. Include in your diagram all data given, and label the two phases present.
60. 9(b)(ii)8 marksUse the diagram drawn in (b) (i) to explain why this mixture cannot be completely separated using fractional distillation.
61. 9(c)(i)2 marksSuggest ONE advantage and ONE disadvantage of carrying out the distillation under increased pressure
62. 9(c)(ii)2 marksSuggest TWO industries that utilize the process.