CSEC Chemistry · May/June 2006 · Paper 2

41 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)a)5 marksComplete Table 1 by filling in the temperatures at which crystals of X reappear in EACH experiment using the information in Figure 1.
2. 1(a)(i)b)5 marksComplete Table 1 by filling in the corresponding solubilities of X (g/100 g water). Use the following equation to calculate the solubility of X at each temperature: Solubility of X (g/100 g water) = (mass of X / mass of…
3. 1(a)(ii)4 marksUsing the graph paper provided on page 4, plot a graph of solubility of X (g/100 g water) against temperature in °C.
4. 1(a)(iii)2 marksWhat deduction about the solubility of X can be made from the graph drawn in Figure 2?
5. 1(a)(iv)3 marksUsing Equation 1 and the graph drawn in Figure 2, calculate the volume of water which is required to just dissolve 2 g of X at 60 °C.
6. 1(a)(v)1 markBased on the graph in Figure 2, calculate the mass of X which would be deposited when 100 g of a solution of X at 60 °C is cooled to 40 °C.
7. 1(b)(i)2 marksComplete Table 2 for the test: To solid Q, add water, stir, filter and then divide the filtrate into four portions. Retain and dry the residue for test (vi) below.
8. 1(b)(ii)2 marksComplete Table 2 for the test: To the first portion of the filtrate from (i) above, add aqueous NaOH until in excess. The observations are: White precipitate formed. Precipitate soluble in excess aqueous NH₃. The…
9. 1(b)(iii)2 marksComplete Table 2 for the test: To the second portion of the filtrate from (i) above, add aqueous KI. The observation is: Yellow precipitate formed. Provide the ionic equation required for the inference.
10. 1(b)(iv)1 markComplete Table 2 for the test: To the third portion of the filtrate from (i) above, add aqueous AgNO₃, followed by aqueous NH₃. The observation is: No observable change. Provide the inference.
11. 1(b)(v)2 marksComplete Table 2 for the test: To the fourth portion of the filtrate from (i) above, add aqueous AgNO₃, followed by aqueous NH₃. Provide the ionic equation required for the inference.
12. 1(b)(vi)2 marksComplete Table 2 for the test: To the dried residue from (i) above, add dilute HNO₃, warm, filter and then divide the filtrate into two portions. The observations are: Vigorous effervescence observed upon addition of…
13. 1(b)(vii)2 marksComplete Table 2 for the test: To the first portion of the filtrate from (vi) above, add aqueous NaOH until in excess. The inference is: Cu²⁺ ions present. Provide the ionic equation required for the inference.
14. 1(b)(viii)2 marksComplete Table 2 for the test: To the second portion of the filtrate from (vi) above, add aqueous NH₃ until in excess. The inference is: Cu²⁺ ions present.
15. 2(a)(i)2 marksWhat differences, if any, are expected between the chemical reactions of chlorine 35 and chlorine 37? Explain your answer.
16. 2(a)(ii)3 marksDetermine the number of electrons, protons and neutrons in the anion formed from the chlorine 37 atom.
17. 2(b)(i)2 marksExplain the term 'ionic crystal'.
18. 2(b)(ii)3 marksUsing the symbols, filled circle for sodium ions and empty circle for chloride ions, fill in on the diagram in Figure 3, the positions occupied by these ions in the sodium chloride crystal.
19. 2(c)(i)3 marksExplain why the melting point of sodium chloride is much higher than that of chlorine.
20. 2(c)(ii)3 marksThe crystal structures of magnesium oxide and sodium chloride are similar. Suggest why the melting point of magnesium oxide is much higher than that of sodium chloride.
21. 3(a)(i)1 markWhich compounds belong to the same homologous series?
22. 3(a)(ii)2 marksState the homologous series to which the compounds you named in (a)(i) belong, and give a reason for placing them in the same homologous series.
23. 3(a)(iii)4 marksDraw fully displayed structures of ANY TWO structural isomers of Compound C. Give the name of EACH isomer you have drawn.
24. 3(b)(i)2 marksState the reagent(s) and condition(s) for Reaction 1.
25. 3(b)(ii)1 markState the name of the process occurring during Reaction 2.
26. 3(b)(iii)3 marksDraw the correct formulae for Compounds E and F and hence write a balanced equation for Reaction 3.
27. 3(b)(iv)2 marksDraw the full structural formula of the organic product that is formed when Compound E reacts with Compound B, the structure of which is shown on page 8.
28. 4(a)(i)1 markWhich element reacts most readily with dilute hydrochloric acid?
29. 4(a)(ii)2 marksWrite a balanced equation to illustrate the reaction occurring in (a)(i) above.
30. 4(a)(iii)4 marksDescribe any difference(s) that may be observed in the reaction indicated in (a)(i) above, if dilute sulphuric acid were to be used instead of dilute hydrochloric acid. Give a reason for your answer.
31. 4(b)(i)1 markIdentify TWO different elements in Table 3 which will combine by covalent bonding.
32. 4(b)(ii)3 marksDraw dot-cross diagrams to illustrate the bonding in b(i) above.
33. 4(c)(i)1 markAn element X (not the actual symbol) has an atomic number of 19. Place element X in the correct position in Table 3.
34. 4(c)(ii)2 marksGive a reason for your answer in (c)(i).
35. 5(a)(i)2 marksSuggest ONE suitable reagent that can be used as Y and ONE as W for the experiment.
36. 5(a)(ii)1 markIdentify the process by which the ammonia gas that is produced at the bottom of the test tube comes in contact with the litmus paper at the mouth of the test tube.
37. 5(a)(iii)2 marksComment on the suitability of using the moist blue litmus paper to identify ammonia gas.
38. 5(a)(iv)4 marksInstead of the litmus test used above, describe ONE OTHER chemical test that can be used to identify ammonia gas. Write a balanced equation to represent the chemical test you have described.
39. 5(b)(i)1 markName the catalyst used in the Haber process.
40. 5(b)(ii)2 marksExplain the importance of using relatively high pressure in this process.
41. 5(b)(iii)3 marksDraw a fully labelled energy profile diagram of the reaction for the production of ammonia during the Haber process. You should name the reactants and products on your diagram.