2022 SASS 3E Chem EOY

End-of-Year Examination 2022/3Exp/Chemistry 3 SECTION A Answer all questions in this section in the multiple choice answer sheet provided. The total mark for this section is 30. 1 In an experiment, a student reacts silver nitrate solution with dilute hydrochloric acid to prepare silver chloride. Which of the following procedures should he perform to recover the silver chloride from the reaction mixture? A Add water and carry out distillation on the mixture. B Filter and evaporate filtrate to dryness. C Filter and recover silver chloride on the filter paper. D Filter the solution obtained till saturated and then cool to obtain the crystals. 2 Chromatogram 1 below shows the results of separation of the coloured inks in a mixture Q, using solvent A. Chromatogram 2 shows the results using the same piece of paper but after it has been rotated anti-clockwise 90 and placed in solvent B. How many different inks are present in mixture Q? A 3 B 4 C 5 D 6 [Turn over rotate anti-clockwise 90 start line x x x Q x x x Q x start line chromatogram 1 chromatogram 2

End-of-Year Examination 2022/3Exp/Chemistry 4 3 Dry test-tubes 1 to 3 are each filled with a different gas and placed in a trough of water. After a short time, the water had risen in test tubes 1 and 3 as shown below. Which gases could the tubes have contained? Tube 1 Tube 2 Tube 3 A ammonia carbon dioxide hydrogen B ammonia hydrogen carbon dioxide C carbon dioxide hydrogen ammonia D hydrogen ammonia carbon dioxide 4 Which of the following solids will not leave any solid residue when heated on an evaporating dish? (i) silver oxide (ii) ammonium carbonate (iii) ammonium chloride A (i) only B (i) and (ii) only C (ii) only D (ii) and (iii) only Tube 1 Tube 2 Tube 3 Water

End-of-Year Examination 2022/3Exp/Chemistry 5 5 A student tried to separate a mixture of food dyes by chromatography. Separation was poor, as shown in the chromatogram below. Which change to the process would improve the result? A Allowing the solvent to rise further up the paper. B Putting a larger spot of the dye mixture onto the paper. C Using enough solvent to cover the baseline. D Using a larger piece of chromatography paper. 6 An ion L2- contains 31 nucleons and 18 electrons. What does its nucleus contain? A 15 protons and 15 neutrons. B 16 protons and 15 neutrons. C 18 protons and 13 neutrons. D 21 protons and 10 neutrons. [Turn over Chromatography paper Solvent front Baseline with spot of substance to be separated

End-of-Year Examination 2022/3Exp/Chemistry 6 7 The proton numbers of elements, X, Y and Z are 4, 6 and 8 respectively. Which of the followi