2024 Prelims HCI H2 Chem P1 (QP)

This document consists of 13 printed pages. HWA CHONG INSTITUTION C2 Preliminary Examination Higher 2 CANDIDATE NAME CT GROUP 2 3 S CENTRE NUMBER S INDEX NUMBER CHEMISTRY Paper 1 Multiple Choice 9729/01 16 September 2024 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Complete the information on the Answer Sheet as shown below. There are thirty questions on this paper. Answer all questions. For each question, there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate.

2 © Hwa Chong Institution 2024 9729/01/C2 Preliminary Examination [Turn Over 1 Heavy water is a form of water whose hydrogen atoms are all replaced by deuterium ( 2H), and is used in nuclear reactors. What are the numbers of electrons and neutrons in D3O+? electrons neutrons A 10 11 B 11 11 C 10 8 D 11 8 2 Which species has two unpaired electrons? A Li+ B Ti+ C Mg D S 3 The Valence Shell Electron Pair Repulsion theory (VSEPR) is used to predict the bond angles of molecules. Which bond angle is correctly predicted by VSEPR? number of bonded electron pairs around central atom number of lone pairs around central atom bond angle A 2 1 105° B 2 2 118° C 3 1 107° D 3 2 90° 4 Use of the Data Booklet is relevant to this question. Some information about the carbonate ion, CO32–, is given. • all carbon-oxygen bonds are of the same length •  electrons are delocalised throughout the structure What is the likely carbon-oxygen bond energy, in kJ mol–1, in the carbonate ion? A 360 B 485 C 740 D 805

3 © Hwa Chong Institution 2024 9729/01/C2 Preliminary Examination [Turn Over 5 Which bonding type corresponds to its description of physical properties? bonding type physical properties 1 giant covalent high melting point, conducts electricity when in solution but not when solid 2 simple covalent low melting point, does not conduct electricity in any state 3 metallic variety of melting points, conducts electricity when solid and when molten 4 ionic low melting point, conducts electricity in any state A 1 and 2 only B 3 and 4 only C 2 and 3 only D 1 and 4 only 6 The volumes and pressures of equal masses of four gases, nitrogen, methane, chlorine and helium, are separately investigated, at constant temperature. The results are plotted on a graph of pV against V. All four gases behave as ideal gases under the conditions chosen. Which plot shows the results for methane? 7 When a sample of a gas is compressed at constant temperature from 15 atm to 60 atm, its volume changes from 76 cm3 to 20.5 cm3. Which statements are possible explanations for this observation? 1 The gas behaves non-ideally. 2 Some of the gas dimerises. 3 There are significant intermolecular forces of attraction between the gas molecules. A 1 only B 1 and 2 only C 1 and 3 only D 2 only

4 © Hwa Chong Institution 2024 9729/01/C2 Preliminary Examination [Turn Over 8 Use of the Data Booklet is relevant to this question. Which diagram shows the correct trends when the melting points of the elements Mg, Al, Si and P are plotted against their first ionisation energies? A B C D 9 Consider the following half equations: Fe2+ → Fe3+ + e– C2O42– → 2CO2 + 2e– In an experiment, 20 cm3 of an acidified solution of 0.020 mol dm–3 of FeC2O4 is oxidised by 15 cm3 of 0.020 mol dm–3 KMnO4. What is the final oxidation state of manganese, given that both Fe 2+ and C 2O42– can be oxidised by KMnO4? A +1 B +2 C +3 D +4 melting point first ionisation energy melting point first ionisation energy  Al  P  Si  Mg  Mg  P  Si  Al melting point first ionisation energy melting point first ionisation energy  Mg  P  Si  Al  Al  P  Si  Mg

5 © Hwa Chong Institution 2024 9729/01/C2 Preliminary Examination [Turn Over 10 Given 1.0 g samples of the same mixture of magnesium carbonate and barium carbonate, which method allows one to determine the mole fraction of magnesium carbonate in the mixture? 1 Add a known volume of 0.1 mol dm −3 HCl(aq), in excess, and back titrate the excess of acid. 2 Add an excess of HCl(aq) and measure, at known temperature and pressure, the volume of CO2 liberated. 3 Add an excess of HCl(aq) followed by an excess of H2SO4(aq); filter, dry and weigh the precipitate. A 3 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 11 Which enthalpy change is always exothermic? A lattice energy B bond breaking C ionisation energy D electron affinity 12 The hydrolysis of sucrose in aqueous solution is catalysed by H+(aq) ions, for example, from hydrochloric acid. sucrose glucose + fructose Which procedure can be used to determine the order of reaction with respect to H+(aq) ions? A Measure the change in pH during the reaction. B Remove samples at various time intervals, quench using excess water, then titrate against a standard solution of sodium hydroxide. C Add a suitable acid-base indicator and watch for the time when the colour changes. D Measure the time taken for a fixed amount of sucrose to be consumed in the presence of different concentrations of hydrochloric acid each time.

6 © Hwa Chong Institution 2024 9729/01/C2 Preliminary Examination [Turn Over 13 Use of the Data Booklet is relevant to this question. Hydrogen peroxide solution decomposes. The equation for this reaction is shown. 2H2O2(aq) → 2H2O(l) + O2(g) A 280 cm3 sample of 2.38 mol dm –3 hydrogen peroxide solution is warmed. The volume of oxygen gas collected over time, measured at r.t.p., is recorded in the graph below. time / min Which statements are correct? 1 The total volume of oxygen gas collected at the end of the reaction is 8.0 dm3. 2 The rate constant for this reaction is 0.017 min–1. 3 The half-life for the reaction will be about 20 min if initial concentration is 1.19 mol dm–3. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 2 volume of O2 / dm3

7 © Hwa Chong Institution 2024 9729/01/C2 Preliminary Examination [Turn Over 14 Which statement about the Haber process for the manufacture of ammonia is correct? A At higher temperatures, the yield goes up and the rate of production of ammonia is faster. B At higher pressure, the yield goes up and the rate of production of ammonia is faster. C In the presence of a catalyst, the yield goes down but the rate of production of ammonia is faster. D When more nitrogen is added, the yield goes down but the rate of production of ammonia is faster. 15 The graph shows how Go changes with temperature for the reaction shown. H2O(g) + CO(g) ⇌ H2(g) + CO2(g) Equimolar amounts of H2O and CO were introduced into a sealed container and allowed to reach equilibrium. Which statement about this equilibrium is true? A The concentration