CAPE Chemistry Unit 1 · 2021 · Paper 2

40 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 'radioactive isotope'.
2. 1(a)(ii)2 marksGive the names and symbols for TWO other forms of radioactive emissions.
3. 1(a)(iii)3 marksList THREE uses of radioactive isotopes.
4. 1(a)(iv)2 marksDetermine the value of A and Z in the equation: ^{241}_{95}\text{Am} \rightarrow \text{ }^{A}_{Z}\text{Np} + \text{ }^{4}_{2}\text{He} + \text{energy}
5. 1(b)2 marksThe element rhenium consists of two isotopes ^{185}\text{Re} and ^{187}\text{Re}, in the atomic ratio of 2:3. Calculate the relative atomic mass of rhenium to three significant figures.
6. 1(c)(i)3 marksList TWO chemicals and ONE piece of apparatus that the student may use to carry out the investigation.
7. 1(c)(ii)1 markDescribe ONE physical change that the student may observe while carrying out the investigation.
8. 1(c)(iii)1 markIdentify the oxidizing agent that the student may use while conducting the investigation.
9. 1(c)(iv)2 marksWrite relevant half equations to illustrate the chemical changes that occur with EACH element used to carry out the investigation.
10. 1(d)(i)1 markDefine the term 'Molar mass'.
11. 1(d)(ii)1 markDefine the term 'Mole'.
12. 1(e)(i)2 marksCalculate the original number of moles of NaOH in 100 cm³ of 0.500 mol dm⁻³ aqueous sodium hydroxide.
13. 1(e)(ii)2 marksCalculate the number of moles of HCl in 27.3 cm³ of 0.600 mol dm⁻³ hydrochloric acid.
14. 1(e)(iii)1 markDeduce the number of moles of unreacted NaOH neutralized by the hydrochloric acid.
15. 1(e)(iv)2 marksCalculate the number of moles of NaOH which reacted with the ammonium sulfate.
16. 1(e)(v)3 marksUse your answer in (e)(iv) to calculate the number of moles and the mass of ammonium sulfate in the sample.
17. 1(e)(vi)1 markWrite the ionic equation, including physical states, for the reaction between ammonium sulfate and aqueous sodium hydroxide.
18. 2(a)(i)3 marksUsing the data from Experiment 1 in Table 1, calculate a value for the rate constant, k, and state its units.
19. 2(a)(ii)4 marksComplete Table 1 by inserting the missing initial [Q], initial [R] and initial rate for the reaction between Q and R.
20. 2(a)(iii)1 markThe order of the reaction with respect to R is 2. State the meaning of the term 'order of reaction' with respect to R.
21. 2(a)(iv)1 markDeduce the overall order of the reaction between Q and R.
22. 2(b)2 marksA fixed mass of marble lumps is reacted with dilute hydrochloric acid at a constant temperature. Outline why the rate of the reaction would increase if the lumps of marble are reduced in size.
23. 2(c)(i)3 marksCalculate the number of moles of iodine and the number of moles of hydrogen iodide in the equilibrium mixture.
24. 2(c)(ii)1 markWrite an expression for Kc for the equilibrium 2HI(g) <=> H2(g) + I2(g).
25. 2(c)(iii)2 marksCalculate the value of Kc at 700 K for the equilibrium 2HI(g) <=> H2(g) + I2(g).
26. 2(c)(iv)1 markCalculate the value of Kc at 700 K for the equilibrium reaction H2(g) + I2(g) <=> 2HI(g).
27. 2(d)(i)2 marksState the meaning of the term 'buffer solution'.
28. 2(d)(ii)1 markIdentify a reagent which could be added to a solution of ammonia in order to form a buffer solution.
29. 2(d)(iii)2 marksConsider the equilibrium HA(aq) + H2O(l) <=> H3O+(aq) + A-(aq). Explain the effect on the buffer solution if the concentrations of hydrogen ions [H+] and hydroxide ions [OH-] are increased separately.
30. 2(d)(iv)3 marksExplain how the molecular structure of amino acids relates to their function as buffers in human blood.
31. 2(e)(i)2 marksIdentify TWO relevant pieces of apparatus and/or materials that may have been used by the students to carry out the experiment.
32. 2(e)(ii)2 marksIdentify TWO relevant experimental steps that may have been taken by the students to determine the pH of the buffer.
33. 3(a)(i)5 marksComplete Table 2 by inserting the missing electronic structure (ES) and the oxidation state (OS) for EACH element listed.
34. 3(a)(ii)4 marksExplain the difference between the trend of the first ionization energy for the Group II elements and the first row transition elements.
35. 3(b)(i)4 marksAccount for the difference in oxidation state between vanadium and calcium.
36. 3(b)(ii)2 marksComment on the observation that calcium carbonate is more thermally stable than magnesium carbonate.
37. 3(c)(i)3 marksExplain the observation in terms of the stability constant of the complex ion formed.
38. 3(c)(ii)2 marksWrite a balanced equation for the reaction occurring when concentrated HCl is added to a pink solution of cobalt(II) chloride.
39. 3(d)(i)5 marksComplete Table 3 to show the observations expected for EACH of the tests on ammonium vanadate.
40. 3(d)(ii)5 marksWrite the formula of the species formed which is responsible for EACH colour observed in (d)(i) in Table 3.