CSEC Chemistry · January 2015 · Paper 2

38 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 marksrecording the temperatures at which the crystals of X reappear in EACH experiment using the information in Figure 1
2. 1(a)(ii)3 marksdetermining and recording the corresponding values for the solubility of X. [At each temperature, Solubility of X = (mass of X / mass of water) × 100; assume 1 cm³ water = 1 g.]
3. 1(b)4 marksUsing the axes on the grid provided on page 5, plot a graph of solubility of X (g/100 g water) against temperature in °C. Draw a best-fit curve through the points plotted.
4. 1(c)1 markWhat deduction about the solubility of X can be made from the graph drawn in 1 (b) above?
5. 1(d)3 marksUsing the equation given in 1 (a) (ii) and the graph drawn in 1 (b), calculate the minimum volume of water which is required to dissolve 2 g of X at 60 °C.
6. 1(e)2 marksDistinguish between 'a solution' and 'a suspension'.
7. 1(f)2 marksBesides temperature, state TWO other factors that affect the rate at which a solute dissolves.
8. 1(g)1 markComplete Table 2 to show the observations and inferences from tests carried out on a solution, M.
9. 2(a)(i)2 marksIn the space below draw a diagram to show the arrangement of electrons in the chlorine atom. [Atomic number = 17]
10. 2(a)(ii)2 marksUsing valence shells only, draw a diagram below to show the bonding which occurs in ICl.
11. 2(b)2 marksState TWO reasons why ICl is expected to have a low melting point.
12. 2(c)3 marksAnalysis of a sample of ICl shows that it consists of molecules of the same molecular formula, but with different molar masses. What is a possible explanation for this?
13. 2(d)2 marksWrite a balanced equation for the reaction which occurs when chlorine is reacted with aqueous potassium iodide.
14. 2(e)(i)2 marksthe change in oxidation number that the iodide ions undergo
15. 2(e)(ii)2 markswhether chlorine is acting as an oxidizing or a reducing agent. State a reason for your answer.
16. 3(a)2 marksState TWO natural sources of hydrocarbons.
17. 3(b)(i)1 markIdentify ONE of these numbered fractions. Fraction number: Fraction name :
18. 3(b)(ii)1 markState ONE use of Fraction 3.
19. 3(c)(i)1 markIdentify the homologous series to which Compound W belongs.
20. 3(c)(ii)2 marksWrite the FULLY DISPLAYED structural formulae of the two molecules that are produced when Compound W is hydrolysed by dilute hydrochloric acid, and state the name of any ONE of the structures.
21. 3(d)(i)1 markState the name of a polymer of glucose, and using THREE glucose units, draw the partial structure of this named polymer in the space provided.
22. 3(d)(ii)2 marksA student is asked to distinguish between a sample of glucose and a sample of its polymer. He adds water to separate portions of glucose and its polymer, and stirs. State the expected observations in EACH case. Glucose:…
23. 3(e)1 markName the type of polymer formed and give ONE use of this polymer.
24. 4(a)(i)2 marksDefine the term 'electrolysis'.
25. 4(a)(ii)4 marksDescribe what happens during the electrolysis of molten sodium chloride. Support your answer with relevant balanced ionic equations.
26. 4(b)3 marksAqueous sodium chloride can be electrolysed using inert electrodes. Discuss the effect that the position of ions in the electrochemical series has on the products of this electrolysis.
27. 4(c)6 marksAluminium is made corrosion resistant by anodizing it. Using a labelled diagram and equations, explain what happens during the anodizing of aluminium.
28. 5(a)(i)5 marksState the name of the anhydride and describe how it is produced. (The conditions for the reactions are necessary but there is no need to write the equations.)
29. 5(a)(ii)4 marksUsing balanced chemical equations, with state symbols, explain how the anhydride is converted to sulfuric acid in the manufacturing process.
30. 5(a)(iii)2 marksSuggest why the anhydride is NOT directly added to water to produce sulfuric acid.
31. 5(b)(i)2 marksSuggest TWO reasons why the alloy, stainless steel, is preferred to pure iron when making cooking utensils.
32. 5(b)(ii)2 marksIn humans, iron is found in haemoglobin which is responsible for the transfer of oxygen throughout the body. Suggest how a lack of iron in the human diet could affect the body.
33. 6(a)(i)2 marksIdentify ONE element that is essential for plant growth and state ONE effect of its deficiency.
34. 6(a)(ii)4 marksDesign an experiment to investigate the effect of the deficiency stated in (a) (i) above on plant growth.
35. 6(b)(i)1 markState ONE problem associated with acidic soils.
36. 6(b)(ii)2 marksUse a balanced ionic equation to explain how the addition of lime can increase the pH of acidic soils.
37. 6(b)(iii)3 marksLime can also cause nitrogen to be lost from soils. State a reason for this. Include a balanced ionic equation with state symbols in your answer.
38. 6(c)3 marksIdentify TWO such disadvantages and suggest ONE way to address ONE of these disadvantages.