CAPE Chemistry Unit 1 · 2013 · Paper 2

33 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 marksDefine the term oxidation.
2. 1(a)(ii)2 marksDefine the term reduction.
3. 1(b)(i)1 markState the colour change observed.
4. 1(b)(ii)6 marksWrite the TWO half equations for the reaction, indicating the changes in oxidation number.
5. 1(b)(iii)2 marksState the roles of the two reagents, potassium manganate(VII) and hydrogen peroxide.
6. 1(c)4 marksDescribe an experiment, including observations, that can be used to compare the oxidizing ability of the elements chlorine, bromine and iodine.
7. 2(a)2 marksDefine the term 'buffer solution'.
8. 2(b)(i)2 marksExplain, using relevant equations, how a buffer solution containing ammonia and ammonium chloride reacts when contaminated with a small quantity of base.
9. 2(b)(ii)2 marksExplain, using relevant equations, how a buffer solution containing ammonia and ammonium chloride reacts when contaminated with a small quantity of acid.
10. 2(c)5 marksCalculate the pH of a buffer solution made from 20.00 cm³ of 0.10 mol dm⁻³ propanoic acid (CH₃CH₂COOH) and 40.00 cm³ of 0.050 mol dm⁻³ sodium propanoate (CH₃CH₂COONa). (The acid dissociation constant, Kₐ, for propanoic…
11. 2(d)(i)2 marksList TWO relevant pieces of apparatus and/or materials that may have been used to carry out the experiment.
12. 2(d)(ii)2 marksDescribe TWO relevant steps taken by the students to determine the pH of the buffer.
13. 3(a)(i)2 marksOutline TWO reasons why aqueous hydroxide ions, OH⁻(aq), are used in the identification of cations.
14. 3(a)(ii)2 marksComplete the table.
15. 3(b)5 marksComplete Table 2 by writing the relevant observations.
16. 3(c)(i)4 marksWrite half equations to explain the observation in test (b)(ii).
17. 3(c)(ii)2 marksIdentify the salts in mixture M.
18. 4(a)2 marksDefine the term 'standard enthalpy of formation'.
19. 4(b)1 markWrite a balanced equation for formation of CaO(s).
20. 4(c)6 marksConstruct a Born-Haber cycle for the formation of CaO(s) showing clearly, using equations, the steps of the enthalpy changes involved.
21. 4(d)4 marksDistinguish between 'exothermic enthalpy change' and 'endothermic enthalpy change', citing enthalpy changes from your Born-Haber cycle in (c) to support your answer.
22. 4(e)2 marksExplain, by writing an equation, how the data from the Born-Haber cycle can be used to calculate the lattice energy of CaO(s).
23. 5(a)(i)4 marksWith the aid of appropriate Boltzmann distribution curves, (using the axes provided on page 12) describe the effect of Temperature on reaction rates.
24. 5(a)(ii)3 marksWith the aid of appropriate Boltzmann distribution curves, (using the axes provided on page 12) describe the effect of Catalyst on reaction rates.
25. 5(b)(i)5 marksUse the information from the table to deduce the rate equation and calculate the overall order of the reaction.
26. 5(b)(ii)a)2 marksCalculate the rate constant.
27. 5(b)(ii)b)1 markCalculate the initial rate of the reaction when [S₂O₃²⁻]₀ = 0.13 mol dm⁻³ and [I⁻]₀ = 0.32 mol dm⁻³.
28. 6(a)2 marksThe atomic radii across the first row of transition elements show a gradual decrease. Outline the reasons for this trend.
29. 6(b)(i)3 marksState the FULL electronic configuration for the ions, Ti³⁺; Fe²⁺; Cr³⁺.
30. 6(b)(ii)2 marksExplain, in terms of electronic configuration, why iron(II) is readily converted to iron(III).
31. 6(c)(i)2 marksState the name of the shape for EACH of the complex ions.
32. 6(c)(ii)1 markState the name of the shape for a complex ion of the formula [ML₄]ⁿ⁺ where M is the central metal and L represents the ligand.
33. 6(d)5 marksExplain carefully how the colour is produced.