August 2022

Kenya Certificate of Secondary Education 2017 Chemistry paper 1 1. Table 1 shows the atomic numbers and the first ionisation energies of three elements. The letters are not actual symbols of the elements. Use it to answer the questions that follow. (a) Explain the trend in first ionisation energy from A to C. (2 mark) […]

Practical 2018 Chemistry paper 3 1. You are provided with: • 0.30 g solid A, magnesium metal • Hydrochloric acid, solution B • 0.15 sodium carbonate, solution C • Methyl orange indicator You are required to determine the: • Enthalpy change, AH per mole, of the reaction between magnesium metal and excess hydrocholoric acid. •

2018 Chemistry paper 2 1. The diagram in figure I shows some natural and industrial processes. Study it and answer the questions that follows (a) Identify the processes labelled: (2 marks) A — Fermentation B — Dehydration C — Addition polymerization / polymerization D — Saponification (b) State the reagents and conditions required for processes

2018 Chemistry paper 2 1. The diagram in figure I shows some natural and industrial processes. Study it and answer the questions that follows (a) Identify the processes labelled: (2 marks) A………………. B………………. C………………. D………………. (b) State the reagents and conditions required for processes B and D. (i) Process B: Reagent…………….(1 mark) Conditions ………… (l

2018 Chemistry paper 1 1. (a) Define a soluble base. (1 mark) A soluble base is a substance that dissociates in water to produce hydroxide ions as the only negative ions. (b) Aqueous solutions of 2M ethanoic acid and 2M nitric(V) acid were tested for electrical conductivity. Which solution is a better conductor of electricity?

 Biology Paper 2 Answer all the questions in the spaces provided. 1. In an experiment to investigate the effect of Sodium chloride on the growth rate in a spinach seedling. seeds were treated with different of sodium chloride. The results are as recorded in the table below. (a) From the results in the table above,

 Chemistry paper 1 1. An atom of element A has mass number 39 and 19 protons. (a) Write the electron arrangements of the atom (1 mark)   2.8.8.1(b) State the period and group to which element A belongs Group 1(½ mark) Period 3(½ mark) (c) State whether the element is a metal or a non-metal. (1 mark)

2020 Chemistry paper 2

 Chemistry Paper 3 (233/3) 1 You are provided with: – 1.6Og of solid A. a dibasic acid. – Solution B containing 4.75g per litre of salt B. – Aqueous sodium hydroxide. solution C. – Phenolphthalein indicator. You are required to prepare a solution of solid A and use it to determine the:- – Concentration of

Chemistry Paper 2 (233/2) 1 The flow chart below shows some of the processes involved in large scale production of sulphuric (VI) acid. Use it to answer the questions that follow. (a) Describe how oxygen is obtained from air on a large scale. (3 marks) (b) (i) Name substance A. (1 mark) (ii) Write an

Chemistry Paper 1 (233/1) 1 (a) What name is given to the process by which alcohol is formed from a carbohydrate? (1 mark) (b) Explain why the solubility of ethane in water is lower than that of ethanol. (2 marks) 2 Complete the nuclear equation below: (a) (c) Give one harmful effect of radioisotopes. (1

Chemistry Paper 3 (233/3) 1 You are provided with:   solution A’ aqueous copper (H) sulphate;  solid B, iron powder;  0.02 M acidified potassium manganate (VII), solution C.You are required to determine the molar heat of displacement of copper by iron. Procedure I Using a burette, place 50.0 cm’ of solution A in a 100