23MIPrelimQP (H2 Chem Paper 1)

Class Adm No Candidate Name: This question paper consists of 14 printed pages and 2 blank pages. 2023 Preliminary Examination Pre-University 3 H2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 20 September 2023 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not turn over this question paper until you are told to do so Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and admission number in the spaces provided at the top of this page and on the Multiple Choice Answer Sheet provided. 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 Multiple Choice Answer Sheet provided. Read the instructions on the Multiple Choice 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 question paper. The use of an approved scientific calculator is expected, where appropriate. FOR EXAMINER’S USE TOTAL (30 marks)

2 For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Which of the following contain the same number of hydrogen atoms? 1 0.10 mol of pentane 2 0.15 mol of but-2-ene 3 0.60 mol of hydrogen gas 4 0.50 mol of steam A 1, 2 and 3 only B 1 and 4 only C 2 and 4 only D 1 and 2 only 2 Ascorbic acid found in fruits and vegetables is believed to help prevent colds. Analysis of ascorbic acid shows that it contains only carbon, hydrogen and oxygen with 40.91% carbon and 4.55% hydrogen by mass. Ascorbic acid has a molar mass of 176 g mol–1. What is the molecular formula of ascorbic acid? A C2H3O2 B C3H4O3 C C6H8O6 D C6H9O6 3 Which of the following species is unable to act as a Lewis acid? A AlCl3 B FeCl3 C BeCl2 D CCl4

3 [Turn over 4 In 2020, a massive explosion took place in Beirut at a warehouse which stocked ammonium nitrate. Ammonium nitrate, NH4NO3 decomposes explosively when heated to form nitrous oxide, N2O and water, H2O. What is the change in the oxidation number of the nitrogen atom that is underlined when this reaction happens? A –2 B +1 C +3 D +4 5 Use of the Data Booklet is relevant to this question. What do the ions 31P3– and 32S2– have in common? A Both ions have more neutrons than protons. B Both ions have more electrons than neutrons. C Both ions have more protons than electrons. D Both ions have an outer electronic configuration of 2s2 2p6. 6 The table below shows the ionisation energy (in kJ mol–1) of four elements labelled A, B, C and D. Element 1st I.E. 2nd I.E. 3rd I.E. 4th I.E. 5th I.E. 6th I.E. A 1012 1907 2914 4964 6274 21 267 B 787 1577 3232 4356 16 091 19 805 C 1521 2666 3931 5771 7238 8781 D 738 1451 7733 10 543 13 630 18 020 Which element above has no electrons in the valence p subshell? A element A B element B C element C D element D

4 7 Which molecules contain at least one bond angle of 120°? 1 C2H4 2 PCl5 3 NF3 A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 8 Elements E, F and G are all in the first two periods of the Periodic Table. Their Pauling electronegativity values, EN, are given in the table. element EN E 1.0 F 2.5 G 3.0 Compounds exist with formulae EG, FG and G2. What is the correct order of increasing boiling point of the three compounds? A EG → FG → G2 B EG → G2 → FG C G2 → FG → EG D G2 → EG → FG 9 When an evacuated glass bulb of volume 300 cm3 is filled with a gas at 450 K and 101 kPa, the mass of the bulb increases by 0.679 g. The gas obeys the ideal gas equation. What is the identity of the gas? A argon B krypton C neon D nitrogen

5 [Turn over 10 Which graph shows the correct plot of pV against p for a fixed mass of ideal gas at two temperatures, T1 and T2, in which T1 > T2? A B C D

6 11 A reaction pathway diagram for the reaction of aqueous barium hydroxide and dilute hydrochloric acid is shown. What is the value of the enthalpy change of neutralisation, Hneut? A c B c – d C c 2 D (c – d) 2 12 The enthalpy change of reaction, ∆Hro, for the following reaction is e kJ mol–1. 2C(s) + 3H2(g) + 3½O2(g) → 2CO2(g) + 3H2O(l) ∆Hro = e kJ mol–1 What is the correct expression to calculate the value of e? A 2 × ∆Hco [CO2(g)] – 3 × ∆Hfo [H2(g)] B 2 × ∆Hco [CO2(g)] + 3 × ∆Hfo [H2O(g)] C 2 × ∆Hfo [CO2(g)] – 3 × ∆Hfo [H2(g)] D 2 × ∆Hfo [CO2(g)] + 3 × ∆Hfo [H2O(l)]

7 [Turn over 13 Nitrogen reacts with hydrogen to form ammonia. N2(g) + 3H2(g) ⇌ 2NH3(g) A mixture of 2.00 mol of nitrogen, 6.00 mol of hydrogen and 2.40 mol of ammonia was allowed to reach equilibrium in a sealed vessel of volume 2 dm 3. When equilibrium was established. 2.32 mol of nitrogen were present in the equilibrium mixture. Which expression will give the value of Kc? A (0.88)2 (1.16)(3.48)3 B (1.76)2 (2.32)(6.96)3 C (1.20)2 (1.16)(3.00)3 D (1.04)2 (1.16)(3.16)3 14 In the reaction below, the concentrations of both J and K are reduced to half their original values whilst keeping the total volume of the solution constant. J(aq) + K(aq) → JK(aq) Simultaneously, the temperature was raised from 298 K to 348 K. Which prediction is definitely true? A A smaller proportion of collisions between particles of J and particles of K will be effective. B The average kinetic energy of particles of J and particles of K will increase. C The rate of the reaction will be unaffected. D The frequency of collisions between particles J and particles of K will halve.

8 15 The rate equation for the reaction S2O82–(aq) + 2I – → 2SO42–(aq) + I2(aq) is rate = k[S2O82–][I–], where k was found to be 0.2 mol–1 dm3 s–1 at temperature T. What is the half-life of the reaction when S2O82– is present in a large excess at concentration of 0.4 mol dm–3 at the same temperature? A 0.35 s B 1.39 s C 3.76 s D 8.66 s 16 The value of pKw at 40 oC is 13.54. What is the pH of an aqueous solution of 0.05 mol dm–3 Ba(OH)2 at 40 oC? A 12.23 B 12.54 C 12.70 D 13.00 17 The numerical values of the solubility products at 25 °C for AgBr and AgI are 7.7 × 10–13 and 8.0 × 10–17 respectively. What is the value of the equilibrium constant for the reaction below? AgBr(s) + I–(aq) ⇌ AgI(s) + Br–(aq) A 6.2 × 10–29 B 1.0 × 10–4 C 9.8 × 101 D 9.6 × 103

9 [Turn over 18 The table gives the concentrations and pH values of the aqueous solutions of three compounds, H, I and L at 25 °C. Each compound could be an acid or a base. H I L concentration /mol dm–3 1.00 1.00 1.00 × 10–4 pH 3 14 4 Which statements are correct? 1 H is a strong acid and I is a strong base. 2 The extent of dissociation of H(aq) is greater than L(aq). 3 When equal volumes of H and I are mixed, a solution of pH > 7 is obtained. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only 19 The formula [CH3]x (where x can be 1 –, 0 or 1 +) can represent an anion, a cation or a free radical. Species with the formula CH3 can act as an electrophile, a free radical or a nucleophile depending on the number of outer shell electrons present on the central carbon atom. How many outer shell electrons must be present for [CH3]x to act in these different ways? [CH3]x as an electrophile [CH3]x as a free radical [CH3]x as a nucleophile A 6 7 8 B 6 8 7 C 7 6 8 D 8 7 6

10 20 Ethene reacts with aqueous