2021 SNGS Prelim P1

This document consists of 18 printed pages. [Turn over Name: _______________________________ ( ) Class:___________ PRELIMINARY EXAMINATION GENERAL CERTIFICATION OF EDUCATION ORDINARY LEVEL __________________________________________________________________________ CHEMISTRY 6092/01 Paper 1 Multiple Choice 31 August 2021 1 hour Additional Materials: Multiple Choice Answer Sheet __________________________________________________________________________ READ THESE INSTRUCTIONS FIRST Write your name, register number and class on the Answer Sheet using a soft pencil. There are forty questions in this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the correct answer and record the corresponding letter using a soft pencil on the separate Answer Sheet. Amendments may be done using a soft eraser. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. The use of an approved scientific calculator is expected, where appropriate. A copy of Periodic Table is provided on page 2. The total number of marks for this paper is 40. For Examiner’s Use Total (40)

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3 1 The chromatogram of the dyes used for a coloured crayon is shown in the diagram below. Which of the following statements can be deduced from the chromatogram? A The colour of the crayon is red. B The Rf value of the yellow dye is lower than that of the blue dye. C The yellow dye is more soluble than the blue dye in the solvent used. D The molecules of the yellow dye are smaller than those of the blue dye. 2 The diagram below shows three reactions of solution X. What are the ions present in solution X? A aluminium ions and nitrate ions B ammonium ions and chloride ions C lead(II) ions and ammonium ions D lead(II) ions and nitrate ions starting line yellow blue solvent front Solution X gas turns moist red litmus paper blue white precipitate white precipitate insoluble in excess aqueous ammonia NaCl (aq) excess NaOH(aq), Al foil, warm NH3(aq)

4 3 Which one of the following could be used to distinguish aqueous solutions of sodium chloride and sodium iodide? A aqueous barium chloride B aqueous silver nitrate C aqueous sodium hydroxide D aqueous sulfuric acid 4 Four gases namely, ammonia, chlorine, hydrogen chloride and hydrogen are placed in separate gas jars containing a strip of moist blue litmus paper and moist red litmus paper each. The gases in w hich gas jar will cause both the moist blue litmus paper and the moist red litmus paper to change colour? A red litmus ammonia blue litmus B blue litmus red litmus chlorine red litmus blue litmus hydrogen chloride C D hydrogen red litmus blue litmus

5 5 A bottle of perfume J was placed 3 metres away from a student. The time taken for the aroma to reach the student was noted. The experiment was repeated with a bottle of perfume K. The time taken for each aroma to reach the student is shown below. perfume time taken / s J 3.4 K 4.6 If the conditions for the two experiments were similar, what conclusion can be made about perfumes J and K? A There is a larger volume of perfume J than perfume K in the bottle. B The aroma of perfume J was stronger than the aroma of perfume K. C The particles in perfume K have higher molecular mass than those in perfume J. D The particles in perfume K are diatomic whereas particles in perfume J are monatomic. 6 X, Y and Z are three different elements . The following diagram shows the arrangement of the valence electrons in the compound formed from elements X, Y and Z : Which of the following statements is/are correct? I Element X can be magnesium. II Element Y belongs to Group VII of the Periodic Table. III Elements Y and Z are bonded together by strong covalent bonds. A I, II and III B I and II only C II and III only D III only X + - Y Z

6 7 Which list of substances is placed under the correct headings? contains ionic bonds only contains covalent bonds only contains both covalent bonds and ionic bonds A Ba(OH)2(aq) SO2(g) NH4Cl(s) B CaCl2(s) C2H5OH(l) CH3COOH(l) C MgF2(s) HCl(g) Na2CO3(s) D PbO(s) SiO2(s) Al2O3(s) 8 Which diagram best represents the structure of calcium oxide? A B C D 9 Lead(IV) chloride has a melting point of -15 °C and boiling point of 50 °C. Which type of structure do you expect lead(IV) chloride to have? A a simple molecular structure with weak covalent bonds B a simple molecular structure with weak Van der Waal’s forces of attraction between molecules C a giant molecular structure with strong covalent bonds between atoms D a giant ionic crystal lattice structure with strong electrostatic forces of attraction 10 An aqueous solution of FeSO 4.(NH4)2SO4.6H2O has a concentration of 0.050 mol/dm3. What is the concentration of the NH4+ ions in this solution? A 0.025 mol/dm3 B 0.050 mol/dm3 C 0.100 mol/dm3 D 0.200 mol/dm3

7 11 When a 10 cm3 sample of a gaseous hydrocarbon was completely burnt in 35 cm3 of oxygen, the total volume of the products formed was 50 cm 3. Which equation represents the combustion of the hydrocarbon? A CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) B C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(g) C C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g) D 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) 12 Silver oxide decomposes when heated to give silver and oxygen. 2Ag2O (s) → 4Ag (s) + O2 (g) When 55.0 g of a sample of silver oxide is heated gently to constant mass, 46.6 g of solid residue is obtained. What is the percentage purity of silver oxide? A 22.7% B 84.7% C 90.9% D 91.0% 13 If 1.38 g of a gaseous nitrogen oxide occupies 360 cm 3 at room temperature and pressure, what is the molecular formula of this gas? A NO B NO2 C N2O D N2O4 14 When 2 moles of electrons is passed through the circuit during the electrolysis of an aqueous solution of a cerium salt, 70 g of cerium (A r of Ce = 140) is deposited at the cathode. Which is likely to be the formula of the cerium ion? A Ce2- B Ce4- C Ce2+ D Ce4+

8 15 An experiment is set up as shown in the diagram below. Both electrodes P and Q are made of graphite. Which of the following gives the correct results as electrolysis progresses? electrolyte mass of P mass of Q A aqueous copper(II) sulfate increases remains unchanged B aqueous copper(II) sulfate remains unchanged increases C aqueous sodium chloride remains unchanged increases D aqueous sodium chloride increases remains unchanged 16 Molten sodium iodide is electrolysed as shown in the diagram. Which statement/s about the electrolysis is/are correct? 1 Oxidation occurs at the cathode. 2 Violet fumes are observed at the anode. 3 A colourless gas is observed at the cathode. A 2 only B 3 only C 1 and 2 only D 1 and 3 only molten sodium iodide Q P P

9 17 Three electrochemical cells are set up using copper metal and three unknown metals, U, V and W as electrodes, immersed in sulfuric acid of the same concentration. The potential differences between the metals are given in the table below. electrochemical cell metals used voltage / V positive electrode 1 Cu, U 0.45 U 2 Cu, V 1.11 Cu 3 Cu, W 2.71 Cu What is the order of decreasing reactivity of the metals, U, V, W and Cu? A W, Cu, V, U B W, V, Cu, U C U, V, Cu, W D U, Cu, V, W 18 When so