CAPE Chemistry Unit 2 · 2015 · Paper 2

34 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 markIdentify the process represented by the equation.
2. 1(a)(ii)1 markState the conditions at A.
3. 1(a)(iii)2 marksWrite the condensed structural formulae of B and C.
4. 1(b)(i)2 marksAccount for the tetravalency of the carbon atom.
5. 1(b)(ii)4 marksUsing appropriate notation and equations, explain the steps involved in the mechanism of the chemical reaction of aqueous bromine with propane (in sunlight) OR aqueous bromine with propene (without sunlight).
6. 1(b)(iii)1 markName the mechanism of the reaction selected in (b)(ii).
7. 1(c)(i)2 marksDescribe the observations expected when aqueous bromine is added to liquid heptane (in sunlight).
8. 1(c)(ii)2 marksDescribe the observations expected when acidified potassium permanganate solution is added to liquid heptene (without sunlight).
9. 2(a)(i)1 markIn a titrimetric analysis, state ONE operation which can affect accuracy.
10. 2(a)(ii)1 markIn a titrimetric analysis, state ONE operation which can affect precision.
11. 2(b)2 marksList TWO requirements which a primary standard reagent that is to be used in a titrimetric analysis must satisfy.
12. 2(c)(i)4 marksUsing the results in Table 1, plot a graph of temperature against volume of acid on the axes provided on page 7.
13. 2(c)(ii)1 markHence, determine the end-point volume of the acid.
14. 2(c)(iii)2 marksCalculate the concentration of the acid.
15. 2(d)4 marksOutline the experimental steps for this type of thermometric titration.
16. 3(a)3 marksList the THREE ways in which the rate of SO3 production can be improved.
17. 3(b)(i)1 markState Le Chatelier's principle.
18. 3(b)(ii)2 marksState the general conditions of temperature and pressure predicted by Le Chatelier's principle to obtain the MAXIMUM yield of SO3.
19. 3(b)(iii)2 marksDescribe how the sulfur trioxide produced is converted to concentrated sulfuric acid.
20. 3(b)(iv)4 marksWrite TWO equations to represent the process described in (b)(iii).
21. 3(b)(v)3 marksOutline the safety considerations that guide the process in (b)(iii).
22. 4(a)4 marksDistinguish between 'addition polymerization' and 'condensation polymerization'.
23. 4(b)3 marksList TWO classes of naturally occurring polymers, giving an example of ONE.
24. 4(c)4 marksUsing a chemical equation, show how terylene can be formed from the monomers ethane-1,2-diol and benzene-1,4-dicarboxylic acid.
25. 4(d)4 marksDeduce the structural formulae of the monomers used to form polymer A shown in the diagram.
26. 5(a)4 marksExplain how chromatography can be used to separate a mixture of dyes.
27. 5(b)(i)2 marksExplain how the presence of the components can be detected.
28. 5(b)(ii)3 marksCalculate the Rf (retention factor) values of Q and R shown in Figure 1.
29. 5(b)(iii)2 marksSuggest TWO reasons for the difference in the Rf values of R and Q.
30. 5(c)4 marksAssess the methods of thin layer chromatography and column chromatography in relation to their uses.
31. 6(a)6 marksUsing an appropriate annotated diagram, describe how chlorine can be produced through use of a diaphragm cell. Include the equations occurring at EACH electrode.
32. 6(b)3 marksExplain why there are health concerns associated with the use and disposal of the diaphragm cell.
33. 6(c)(i)3 marksAssess the impact of CFCs on the environment.
34. 6(c)(ii)3 marksSuggest THREE reasons to support the statement: 'Like CFCs, the products of the combustion of fossil fuels also have a negative effect on the environment.'