CAPE Chemistry Unit 1 · May/June 2023 · Paper 2

38 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 markState Boyle's law.
2. 1(a)(ii)1 markState Charles' law.
3. 1(b)4 marksList FOUR assumptions made about gas molecules in the kinetic molecular theory with reference to ideal gases.
4. 1(c)4 marksA flask has a mass of 47.392 g when empty, and 47.816 g when filled with acetone vapor at 100 °C and 745 mm Hg. If the volume of the flask is 247.3 mL, calculate the molar mass of the acetone. (R = 0.0821 L atm mol⁻¹…
5. 1(d)(i)2 marksState Hess' law.
6. 1(d)(ii)6 marksConstruct a Born–Haber cycle for the formation of lead (II) fluoride, PbF₂(s), showing clearly, using equations, the steps of the enthalpy changes involved.
7. 1(d)(iii)3 marksUsing the data in Table 1, calculate the lattice energy of PbF₂(s).
8. 1(e)(i)1 markState the effect of ionic charge on the magnitude of the lattice energy.
9. 1(e)(ii)1 markState the effect of ionic radius on the magnitude of the lattice energy.
10. 1(f)(i)2 marksWrite the simplest ionic equation for the formation of the yellow precipitate when silver nitrate solution acidified with dilute nitric acid is added to an aqueous solution containing iodide ions.
11. 1(f)(ii)1 markState the result observed when concentrated ammonia solution is added to this yellow precipitate.
12. 1(f)(iii)1 markState why the silver nitrate solution is acidified when testing for iodide ions.
13. 1(f)(iv)1 markExplain why dilute hydrochloric acid is not used to acidify the silver nitrate solution in this test for iodide ions.
14. 1(g)2 marksDescribe the result observed when chlorine water is added to a solution of potassium bromide, followed by aqueous silver nitrate.
15. 2(a)(i)2 marksExplain the term 'dynamic equilibrium'.
16. 2(a)(ii)1 markState what is observed when dynamic equilibrium is reached in the reaction above.
17. 2(a)(iii)1 markState Le Chatelier's Principle.
18. 2(a)(iv)1 markWrite the expression for K_p for the reaction above.
19. 2(a)(v)2 marksIn the space provided, draw a graph to show how the concentrations of N₂O₄(g) and NO₂(g) are expected to change as the reaction proceeds towards equilibrium.
20. 2(a)(vi)2 marksAccount for the shape of the graph drawn in (a)(v).
21. 2(a)(vii)2 marksState what is observed when the sealed tube is cooled to 0 °C. Outline the reason for what is observed.
22. 2(b)(i)2 marksState the difference in behaviour between a strong acid and a strong base according to the Brønsted-Lowry Theory.
23. 2(b)(ii)1 markWrite the reaction for the dissociation of CH₃COOH.
24. 2(b)(iii)6 marksComplete Table 2, using the variable x to generate expressions for the equilibrium concentrations of the reaction components for a 0.30 M solution of CH₃COOH.
25. 2(b)(iv)1 markGenerate an expression for K_a for this reaction using equilibrium expressions obtained in (b)(iii).
26. 2(b)(v)3 marksCalculate the pH of a 0.30 M solution of CH₃COOH at 25 °C, if x is 0.0023 M.
27. 2(c)(i)3 marksFigure 1 is a diagram of a voltaic cell. Give the correct labels that correspond to the letters A, B and C on the voltaic cell.
28. 2(c)(ii)1 markDescribe an observation expected during electrolysis.
29. 2(c)(iii)1 markDescribe an observed change if the cell components are based on the cell type Zn(s) | Zn²⁺(aq) || Cu²⁺(aq) | Cu(s).
30. 2(c)(iv)1 markState a chemical compound which is in the salt bridge.
31. 3(a)(i)3 marksIn Table 3, write the formulae for the oxides of the elements in Period 3, excluding chlorine and argon.
32. 3(a)(ii)3 marksIn Table 3, write the oxidation number for the element of EACH oxide in Period 3, excluding chlorine and argon.
33. 3(a)(iii)2 marksExplain the nature and variation of the oxidation numbers for the elements in the oxides in Table 3.
34. 3(b)2 marksWrite the equation for the reaction between the oxide of phosphorus and cold water.
35. 3(g)(i)1 markWhich of the halogens bring about the maximum change in oxidation number of sulfur?
36. 3(g)(ii)1 markWrite ONE full ionic equation to represent this change.
37. 3(h)(i)1 markIdentify element Z.
38. 3(h)(ii)4 marksExplain the reaction taking place in EACH of the tests above. Include balanced equations in your explanation.