Set 13 Chemistry [Paper] 2

1 SECTION A (60 Marks) Answer only three questions from this section . 1. Write equations to show how the following compounds can be synthesised . a). Propan-1-ol from Propyne (04 marks) b). 2,2-dibromopropane from Propan-1-ol (04 marks) c). Propanoneoxime from Benzene (04 marks) d). from Phenol (04 marks) e). from Benzoic acid (04 marks)CH2OH CN 2. Define the following terms. (@01 mark) i) Colligative property ii) Osmotic pressure b) i) Describe an experiment to determine the molecular mass of mannitol by osmotic pressure method. (07 marks) ii) State three limitations of this method. (01½ marks) c) The table below shows the osmotic pressure of a solution of mannitol of various concentrations at 250C. Concentration of the solution (gdm-3) 1.5 3.0 4.5 6.0 7.5 9.0 10.5 Osmotic pressure of the solution (atm) 0.20 0.40 0.60 0.81 1.05 1.20 1.40 i) Plot a graph of osmotic pressure against concentration of the solution. (03½ marks) ii) Explain the shape of the graph. (03 marks) iii) Use your graph to determine the relative molecular mass of mannitol. (03 marks) 2 3. Sodium, aluminium, silicon, phosphorus, sulphur and chlorine belong to period (III) elements of the periodic table . (a) Predict and explain the differences in the melting points of the elements . (04 marks) (b) Describe the reactions of: (i) Aluminium, silicon and phosphorus with sodium hydroxide solution . (04 marks) (ii) Hydride of sodium, silicon, and sulphur with water . (03 marks) (iii) Chlorides of aluminium, silicon and phosphorus with water. (04 marks) (c) The table below shows the melting points of oxides of period (III) elements. Oxide Na2O MgO Al2O3 SiO 2 P2O5 SO2 Cl2O7 Melting point (K) 1,548 3,100 2,280 1,830 833 303 182 Explain the differences in melting points. (05 marks) 4.(a) Describe with the aid of a labelled …