CAPE Chemistry Unit 1 · May/June 2019 · 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)3 marksExplain how the atomic emission spectrum of hydrogen is produced.
2. 1(a)(ii)1 markIdentify the series of lines in Figure 1.
3. 1(a)(iii)4 marksAssess how the series of lines in Figure 1 provides evidence for discrete energy levels in hydrogen.
4. 1(a)(iv)4 marksIn Figure 2, draw the electron transitions occurring between energy levels associated with the origin of the lines in the visible region of the hydrogen spectrum.
5. 1(b)(i)1 markWrite the electronic configuration of oxygen in its ground state using s, p notation.
6. 1(b)(ii)2 marksDraw the shapes of the s and p orbitals.
7. 1(b)(iii)4 marksUse the VSEPR theory to deduce the arrangement of the orbitals and the shape or bond angles around each of the oxygen atom in a molecule of water (H2O) and the hydronium ion (H3O+).
8. 1(b)(iv)3 marksExplain why the density of ice is lower than expected.
9. 1(c)3 marksUsing the bond energies from Table 1, determine the enthalpy of reaction, ΔH_r.
10. 1(d)5 marksOutline an experiment to determine the heat of solution of ammonium nitrate, including a labelled diagram of the apparatus, data to be collected, and how the data collected can be used to determine the heat of solution.
11. 2(a)(i)2 marksUsing the Bronsted-Lowry theory, differentiate between a 'strong acid' and a 'weak acid'.
12. 2(a)(ii)2 marksCarbonic acid forms a weak acidic solution in water. Write an equation to represent the change when carbonic acid is dissolved in water.
13. 2(a)(iii)2 marksState TWO weak acids other than carbonic acid.
14. 2(b)(i)2 marksDefine EACH of the terms pH and pKa.
15. 2(b)(ii)2 marksCalculate the pH of a 0.100 mol dm^-3 aqueous solution of carbonic acid (Ka of carbonic acid = 4.5 x 10^-7 at the experimental temperature).
16. 2(b)(iii)3 marksDetermine the pKa of carbonic acid and compare its strength with an aqueous solution of hydrogen sulfide (Ka of hydrogen sulfide = 8.9 x 10^-8).
17. 2(b)(iv)3 marksSketch a labelled graph to show the pH changes which occur during the titration of 25 cm^3 of 0.10 mol dm^-3 carbonic acid with 0.10 mol dm^-3 of sodium hydroxide solution.
18. 2(c)(i)1 markDefine the term 'buffer solution'.
19. 2(c)(ii)2 marksState the components of TWO buffer systems in the blood.
20. 2(c)(iii)2 marksExplain, using an equation, how ONE of the buffer systems in (c)(ii) operates to maintain the pH of blood when acid is added.
21. 2(d)(i)1 markWrite the expression for the solubility product of calcium hydroxide.
22. 2(d)(ii)3 marksCalculate the solubility of calcium hydroxide in g dm^-3 (Ksp Ca(OH)2 = 5.5 x 10^-6 mol^3 dm^-9).
23. 2(d)(iii)5 marksOutline the experimental steps required to determine the solubility product of calcium hydroxide.
24. 3(a)(i)2 marksWrite the equation, including state symbols, for the first ionization energy of magnesium.
25. 3(a)(ii)2 marksExplain why there is a general increase in the first ionization energies across the period from sodium to argon.
26. 3(a)(iii)2 marksExplain why the first ionization energy of magnesium is greater than that of aluminium.
27. 3(b)4 marksWrite a balanced equation to show the reaction between water and EACH of Na2O and SO3.
28. 3(c)(i)5 marksDescribe an experimental method with expected results to determine the acid-base nature of the following three Period 3 chlorides: NaCl, MgCl2, and SiCl4.
29. 3(c)(ii)4 marksWrite a balanced equation to show the reaction between water and EACH of MgCl2 and SiCl4.
30. 3(d)(i)1 markDefine the term 'transition element'.
31. 3(d)(ii)3 marksList THREE characteristic properties of transition elements other than forming coloured compounds.
32. 3(d)(iii)2 marksState the colour of the ions B and C.
33. 3(d)(iv)5 marksAccount for the fact that unlike Cu2+ compounds, Zn2+ compounds are normally colourless.