CAPE Chemistry Unit 2 · 2011 · Paper 2

32 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)5 marksComplete Table 1 by indicating simple test tube reactions to distinguish between each given pair of compounds and recording the expected observations.
2. 1(b)(i)4 marksShow the steps involved in the mechanism of the reaction between A and sodium hydroxide using curved arrows to show the movement of electrons.
3. 1(b)(ii)1 markState the name of the reaction mechanism outlined in (b)(i).
4. 1(c)(i)4 marksState the reagent(s) used for the conversion at EACH step (Step 1, Step 2, and Step 3).
5. 1(c)(ii)1 markName the process which occurs in Step 3 of the reaction.
6. 2(a)3 marksDistinguish between the terms 'precision' and 'accuracy'.
7. 2(b)2 marksList THREE pieces of apparatus that could be used to accurately measure 50 cm³ of a liquid.
8. 2(c)(i)2 marksComplete Table 2 by calculating the standard deviation (SD) of EACH of the four sets of results using the provided formula.
9. 2(c)(ii)4 marksEvaluate the results obtained by EACH student by commenting on the accuracy and precision of EACH set of titre volumes.
10. 2(d)4 marksOutline the experimental steps that should be taken by a student to calibrate a 10 cm³ pipette.
11. 3(a)3 marksOutline the THREE principles of the primary distillation of crude oil.
12. 3(b)(i)1 markDefine the term 'cracking'.
13. 3(b)(ii)1 markDefine the term 'reforming'.
14. 3(c)2 marksWrite the balanced equation representing the cracking of octane to produce two hydrocarbons, one of which is butane.
15. 3(d)3 marksState THREE uses of the products of cracking in the manufacture of petrochemicals.
16. 3(e)(i)2 marksState the names of the substances A and B in the suspension.
17. 3(e)(ii)2 marksState what would be observed after a period of time in the conical flask and the beaker.
18. 3(e)(iii)1 markGive a reason why very high temperatures must be avoided during fermentation.
19. 4(a)(i)2 marksDefine the term 'structural isomerism'.
20. 4(a)(ii)4 marksIdentify TWO types of structural isomers, giving an example of EACH.
21. 4(b)4 marks10 cm³ of a gaseous hydrocarbon were mixed with 45 cm³ of oxygen and exploded. After cooling to room temperature, the residual gases occupied 30 cm³. By absorption with NaOH solution, a decrease in volume of 20 cm³ was…
22. 4(c)5 marksExplain the difference in acidity of alcohols, phenols and carboxylic acids, making reference to acid strength, inductive and conjugative effects.
23. 5(a)(i)1 markState the source of absorption in UV/VIS spectroscopy.
24. 5(a)(ii)3 marksUse an energy level diagram to show the electronic transitions that can occur in UV/VIS spectroscopy.
25. 5(b)(i)1 markDefine the term 'chromophore'.
26. 5(b)(ii)1 markSuggest the chromophore in naphthalene (P) that is responsible for the absorption of UV radiation.
27. 5(b)(iii)3 marksA sample of the solution in a cell of path length 1 cm gave an absorbance of 1.2 at a wavelength of 312 nm and an extinction coefficient of 288 dm³ mol⁻¹ cm⁻¹. Calculate the concentration of P in the solution.
28. 5(c)4 marksExplain the use of calibration curves and standard solutions in UV/VIS analysis.
29. 5(d)2 marksList TWO uses of UV/VIS spectroscopy in chemical analysis.
30. 6(a)4 marksIdentify the unlabelled components, A, B, C and D, in Figure 2.
31. 6(b)2 marksState TWO human activities that have led to the disturbance of the balance of the nitrogen and carbon cycles.
32. 6(c)9 marksExplain, with the use of relevant equations, the processes which allow for the maintenance of the concentration of ozone in the stratosphere, discussing oxygen formation and decomposition.