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 following lists give the correct formulae of the compounds formed between them? A XZ YZ 2 XYZ 2 B XZ YZ2 XYZ 3 C X 2Z YZ XYZ 3 D X2Z YZ XYZ 4 8 The models and formulae for two molecules are shown below. Which of the following, A, B, C or D, shows the correct model of a molecule for the compound formed between Y and Z? A B C D 9 The boiling point of water is 100°C. The melting point of potassium chloride is 770°C. What is most likely the boiling point of a sample of water containing a small quantity of potassium chloride? A 90°C B 104°C C 456°C D 773°C XY3 ZX

End-of-Year Examination 2022/3Exp/Chemistry 7 10 Consider the following chemical equation: u NH3(g) + v CuO(s) → w Cu(s) + x H2O(l) + y N2(g) Which row is correct? u v w x y A 1 2 3 2 1 B 1 1 2 3 2 C 2 3 3 3 1 D 2 3 1 2 2 11 TUV is a new indicator that changes colour according to the pH range shown below: pH range Colour 0 - 2 Yellow 3 - 6 Blue 7 - 14 Colourless Which pair of substances present in a mixture can be distinguished by the addition of TUV to each sample separately? A Aqueous ammonia and sodium chloride solution B Dilute carbonic acid and potassium chloride solution C Dilute ethanoic acid and rainwater D Dilute hydrochloric acid and dilute sulfuric acid [Turn over

End-of-Year Examination 2022/3Exp/Chemistry 8 12 The following diagrams are used to illustrate different substances I to IV. Diagram I Diagram II Diagram III Diagram IV Which row identifies the correct diagrams? a mixture of elements and compounds a mixture of elements molecules of an element molecules of a compound A I III IV II B I III II IV C III I IV II D III I II IV

End-of-Year Examination 2022/3Exp/Chemistry 9 13 The table shows the melting and boiling points of sulfur, lead(II) bromide and dilute sulfuric acid. Substance Melting Point/ 0C Boiling Point/ 0C Sulfur 119 445 Lead(II) bromide 370 910 Dilute sulfuric acid -2 102 The bulb lights up when the apparatus shown is set up. Which of the following correctly describes the substances present in beaker P and beaker Q? Beaker P at 20 0C Beaker Q at 450 0C A B C D Dilute sulfuric acid Dilute sulfuric acid Lead(II) bromide Sulfur Sulfur Lead(II) bromide Dilute sulfuric acid Dilute sulfuric acid 14 Which of the following substances contains both ionic and covalent bonds? A Calcium carbonate B Iron (II) sulfide C Sodium chloride D Sulfur dioxide [Turn over Beaker P Beaker Q

End-of-Year Examination 2022/3Exp/Chemistry 10 15 Which of the following does not contain the same number of electrons as a sulfide ion, S2− ? A Al3+ B Ar C H2S D P3− 16 The chemical formulae of antimony oxide and potassium phosphate are Sb2O3 and K3PO4, respectively. What will be the formula of antimony phosphate? A SbPO4 B Sb2PO4 C Sb2(PO4)3 D Sb3PO4 17 What is the oxidation state of sulfur in S2O32− ? A +4 B +3 C +2 D −2 18 Which of the following statements about the reaction shown is incorrect? 3Na 2SO3 + Cr2O72− + 8H+  3Na2SO4 + 2Cr3+ + 4H2O A Na2SO3 is acting as a reducing agent. B The oxidation state of sulfur is increased from +4 to +6. C The solution changes from orange to green. D The oxidation state of chromium is increased from −6 to +3.

End-of-Year Examination 2022/3Exp/Chemistry 11 19 Which of the following statements describing acids is correct? I All acids are liquids. II All acids consist of oxygen. III All acids react with any metals to give hydrogen gas. IV All acids produce hydrogen ions when ionized in water. A IV only B I and IV only C III and IV only D I, II, III and IV 20 The diameters of some particles are shown in the table. Particle Size in nm (10−9m) Water molecule Oil molecule Protein molecule Virus particle 0.2 1.0 10.0 50.0 An aqueous waste liquid contains a suspension of visible sand particles mixed with oil, protein, and viruses. By using two filters with pores of different sizes, it is intended to separate the mixture to obtain the protein. oil and water protein trapped here waste water Filter Y Filter X Which row shows the suitable diameter of the pores in each filter? Filter X Filter Y A 20.0 nm 0.2 nm B 20.0 nm 2.0 nm C 100.0 nm 2.0 nm D 100.0 nm 10.0 nm [Turn over

End-of-Year Examination 2022/3Exp/Chemistry 12 21 Which of the following solutions will have the lowest pH? A 0.1 mol/dm3 hydrochloric acid B 0.1 mol/dm3 sodium hydroxide C 0.1 mol/dm3 sulfuric acid D 0.2 mol/dm3 ethanoic acid (CH3COOH) 22 When a salt Y is heated w