2023 XMS P1 PRELIM QP

3 6092/Chemistry/Paper 1/2023 Preliminary Exam 1 The diagram shows how to obtain pure water from salt solution. Where do water molecules lose energy? 2 A student sets up the following apparatus to collect a gas. What is the possible identity of the gas and drying agent? gas drying agent A hydrogen chloride calcium oxide B hydrogen chloride concentrated sulfuric acid C ammonia concentrated sulfuric acid D ammonia calcium oxide

4 6092/Chemistry/Paper 1/2023 Preliminary Exam 3 Strontium is used in fireworks to produce crimson flames. The graph below shows the relative masses of three naturally occurring isotopes of strontium and their percentages in a sample of strontium. What is the relative atomic mass of naturally occurring strontium? A 86.5 B 87.4 C 87.7 D 88.0 4 The Rf values for the colours, E, F, G and H, in four different solvents are shown in the table. solvent water ethanol propanone hexane E 0.3 0.5 0.6 0.5 F 0.3 0.7 0.9 0.2 G 0.7 0.8 0.3 0.1 H 0.1 0.6 0.6 0.2 Which solvent could be used to separate a mixture of all four colours E, F, G and H? A water B ethanol C propanone D hexane relative isotopic mass percentage of isotope in sample 85 86 87 88

5 6092/Chemistry/Paper 1/2023 Preliminary Exam 5 Hydrogen sulfide, H2S, is a colourless and poisonous gas. The melting point of hydrogen sulfide is −82 C and the boiling point is −60 C. Which statement correctly describes the particles of hydrogen sulfide at −75 C? A closely packed, moving freely B closely packed, vibrating slightly C far apart, moving freely D far apart, vibrating slightly 6 An ion contains 8 protons, 8 neutrons and 10 electrons. What is its nucleon number? A 8 B 16 C 18 D 26 7 The diagram shows the structure of a covalent compound containing the element hydrogen, H, and the unknown elements X, Y and Z. How many outer electrons do each of the three elements, X, Y and Z possess? X Y Z A 3 6 5 B 4 2 6 C 4 6 5 D 4 6 3

6 6092/Chemistry/Paper 1/2023 Preliminary Exam 8 Whisky is a beverage composed of mainly water and ethanol. Ethanol boils at 78 °C. A sample of Scotch Whisky that is made up of 40% of ethanol by volume is distilled using fractional distillation. Which graph shows the change in concentration of ethanol in the sample as the distillation proceeds? A B C D 9 Q is an element in the Periodic Table. Which of the following represents an isotope of Q35 81 ? A Q37 81 B Q33 81 C Q35 79 D Q33 79 10 Which method is most suitable for preparing calcium nitrate crystals? A Add excess calcium carbonate to nitric acid. Filter and crystallise the filtrate. B Add equal volumes of aqueous calcium chloride and aqueous sodium nitrate together and filter. C Add excess nitric acid to calcium oxide. Crystallise the mixture. D Titrate equal volumes of nitric acid and calcium chloride. Crystallise the mixture.

7 6092/Chemistry/Paper 1/2023 Preliminary Exam 11 Some properties of substances J, K, L and M are given in the table below. Which classification of the substances as an element, a mixture or a compound is correct? substance percentage composition by mass electrical conductivity when solid effect of heat J fixed yes solid burns brightly to form an oxide. K fixed no solid decomposes to form simpler substances. L varies yes solid melts M varies no liquid burns to form carbon dioxide and water. element compound mixture A K J L, M B J, K M L C J K, L M D J K L, M 12 Which statement(s) is/are true about 1.0 mol/cm3 of dilute ethanoic acid, 1.0 mol/cm3 of dilute sulfuric acid and 1.0 mol/cm3 of dilute hydrochloric acid? 1 All three acids have the same concentration of hydrogen ions. 2 The rate of reaction with magnesium carbonate is the same for hydrochloric acid and sulfuric acid. 3 The rate of reaction with magnesium is fastest for sulfuric acid and slowest for ethanoic acid. 4 Sulfuric acid has twice the concentration of hydrogen ions as compared to hydrochloric acid. A 1 and 2 B 1, 2 and 3 C 3 only D 3 and 4

8 6092/Chemistry/Paper 1/2023 Preliminary Exam 13 Which oxide is insoluble in aqueous sodium hydroxide? A iron(III) oxide B carbon dioxide C lead(II) oxide D sulfur dioxide 14 512 g of sulfur vapour has the same volume as 64 g of oxygen gas at the same temperature and pressure. What is the formula of a molecule of sulfur? A S B S4 C S8 D S16 15 Which of the following is the correct ionic equation for the reaction between aqueous sodium carbonate and dilute hydrochloric acid? A H+ + OH- → H2O B 2HCl + Na2CO3 → H2O + CO2 + 2NaCl C 2H+ + Na2CO3 → H2O + CO2 + 2Na+ D 2H+ + CO32- → H2O + CO2 16 0.30 mol of a compound contains 14.4 g of oxygen, 4.8 g of hydrogen and 28.8 g of carbon. What is the empirical formula of the compound? A C2H5O B C3H5O C C8H16O3 D C29H4O14

9 6092/Chemistry/Paper 1/2023 Preliminary Exam 17 Which volume of 0.1 mol/dm3 sulfuric acid is required to react completely with 20 cm3 of 0.2 mol/dm3 lithium hydroxide solution? A 20×0.2 0.1 B 20×0.2 2 ×0.1 C 20×0.1 0.2 D 20×0.1 2 ×0.2 18 An excess of dilute nitric acid was added separately to the following. 1 4.8 g of magnesium 2 8.4 g of magnesium carbonate 3 4.0 g of magnesium oxide, then warmed Which of the following options is correct? A The number of moles of magnesium nitrate formed is the greatest in reaction 1. B The number of moles of magnesium nitrate formed is the greatest in reaction 2. C The number of moles of magnesium nitrate formed is the greatest in reaction 3. D The number of moles of magnesium nitrate formed is the same for all 3 reactions. 19 Which pair of statements describes the differences between the conduction of electricity in the electrolyte and the conduction of electricity in a platinum electrode during electrolysis? conduction of electricity in electrolyte conduction of electricity in platinum electrode 1 current due to movement of ions current due to movement of ions and electrons 2 charged particles move in opposite directions charged particles move in a single direction 3 results in a chemical change does not result in a chemical change A 2 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 only

10 6092/Chemistry/Paper 1/2023 Preliminary Exam 20 A student carried out an experiment involving the electrolysis of concentrated copper(II) chloride in cell A and concentrated sodium chloride in cell B using inert electrodes. What are the ionic equations that occur at electrode X and Y at the start of the electrolysis? electrode X electrode Y A 4OH – → 2H2O + O2 + 4e – 2H+ + 2e – → H2 B 2Cl – → Cl2 + 2e – 2H+ + 2e – → H2 C 4OH – → 2H2O + O2 + 4e – Na+ + e – → Na D 2Cl – → Cl2 + 2e – Na+ + e – → Na 21 The diagram below shows a simple cell. metal X voltmeter reading when connected to copper/ V magnesium 3.2 iron zinc 2.4 lead 0.8 Study the information given in the table above. What could be the possible voltmeter reading for iron? A 0.5 V B 1.7 V C 2.8 V D 3.9 V

11 6092/Chemistry/Paper 1/2023 Preliminary Exam 22 In a particular two-step chemical reaction, step 2 occurs immediately after step 1 is complete. X is converted to Y in step 1, while Y is converted to Z in step 2. The enthalpy change of both reactions are also given. sign of ΔH energy change/kJ step 1 negative 200 step 2 positive 350 Which graph shows the temperature change that will occur for the two-step chemical reaction? A B C D 23 The energy profile diagram of a reaction is given. Which reaction cannot be represented by this diagram? A C2H4 (g) + 3O2 (g) → 2CO2 (g