Set 1 Chemistry [Paper] 2

1 SECTION A (60 Marks) Answer only three questions from this section . 1. (a) State: (i) Partition law. (01 m ark) (ii) Three limitation of partition law. (01½ marks) b) Describe how the partition coefficient for butane -1,4-dioic acid between trichloromethane and water can be determined. (06 mar ks) c) In an experiment, an aqueous solution containing 4.0 g of butane - 1,4-dioic acid dissolved in 1 dm3 to of solution was shaken with 200cm3 of trichloromethane. Calculate the percentage by mass of butane -1,4-dioic acid that remained in the aqueous layer. (The partition coefficient between trichloromethane and water = 22.5) (03½ m arks) d) (i) Define the term steam distillation. (01 m ark) (ii)State three principles of steam distillation. (03 marks) (iii) A mixture of phenylamine and water was steam distilled at 98oC and 101.325 kPa. The saturated vapour pressure of water at 98oC is 96.000 kPa. Calculate the percentage of by mass of phenylamine in the distillate. (03 m arks) 2.(a) Explain the trend in the boiling points of group VII elements. (03 m arks) b) Explain why hydrogen fluoride: (i) Is a weaker acid in a dilute aqueous solution than in a concentrated solution? (03 m arks) (ii) Has a higher boiling than hydrogen iodide. (03 m arks) c) Write the equation for the reaction between hydrogen fluoride and silicon (IV) oxide. (01 m ark) d) Describe the reactions of group VII elemen ts with sodium hydroxide. (07 m arks) e) Write the equation for the reaction between sulphuric acid and (i) Sodium chloride. (01 m ark) 2 (ii) Potassium bromide. (01 m ark) (iii)Sodium iodide. (01 m ark) 3. A compound Z contains 73.32% by mass carbon, 6.38% by mass hydrogen and the rest being oxygen. When 1.5 g of Z was dissolved in 20.9 …