2024 Prelims VJC H2 Chem P1 (QP)

© VJC 2024 9729/01/PRELIM/24 [Turn over 1 VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 19 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. Write your index number, name and CT group on the Answer Sheet. There are thirty questions. 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. A Data Booklet is provided. 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. This document consists of 12 printed pages.

© VJC 2024 9729/01/PRELIM/24 2 For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 Which arrangement of the four e lectrons of highest energy corresponds to the electronic configuration of a Group 14 element at its ground state? A 2s22p2 B 1s22s2 C 2s12p3 D 2s22p3 2 The table below shows the sixth ionisation energies of four consecutive elements in the Periodic Table. element W X Y Z sixth ionisation energy / kJ mol–1 19800 21300 8500 9360 What is the formula of the fluoride of W? A WF3 B WF4 C WF5 D WF6 3 Boron trifluoride, BF3, is very difficult to handle due to its high reactivity at room temperature. 1 mole of BF3 can react with 1 mole of dimethyl ether, CH3OCH3 to form compound J. Which statements are correct? 1 Lone pair electrons on oxygen in CH3OCH3 is donated to the vacant orbital of boron in BF3. 2 The bond angle around boron changes from 120 ° in BF 3 to 109.5 ° in compound J. 3 The molecular shape around oxygen changes from bent in CH 3OCH3 to trigonal planar in compound J. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only 4 The boiling point of water (100°C) is greater than that of NH3 (–33.3°C). Which statement does not explain the relative boiling points of H2O and NH3? A The water molecule has a greater permanent dipole than the NH3 molecule. B Each hydrogen bond formed between water molecules is stronger than that formed between NH3 molecules. C There are, on average, more hydrogen bonds between water molecules than there are between NH3 molecules. D The O–H bonds in water are stronger than the N–H bonds in NH3.

© VJC 2024 9729/01/PRELIM/24 [Turn over 3 5 Deuterium, 2H, is an isotope of hydrogen. In an experiment, 18.0 g of gas A at 40°C is found to occupy the same volume as 0.6 g of a deuterium gas, 2H2, at 20°C. The pressure of gas A is twice of that of the deuterium gas. What is the relative molecular mass of gas A? A 32.0 B 60.0 C 64.1 D 120 6 V and Z are both elements in Period 3 of the Periodic Table. Each element forms one stable ion that does not contain another element. The atomic radius and the ionic radius of each element described above is shown. element atomic radius / nm ionic radius / nm V 0.186 0.095 Z 0.099 0.181 Which statement is correct? A Ions of V and Z have the same number of full electronic shells. B Z has a greater electronegativity than V. C Ions of Z are positively charged. D V has more valence electrons than Z. 7 Which statements about the behaviour of the Group 2 elements , magnesium to barium, or their compounds are correct? 1 The thermal stability of their carbonates increases. 2 The reaction between elements with water becomes less vigorous. 3 The electronegativity of elements decreases. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 3 only

© VJC 2024 9729/01/PRELIM/24 4 8 X, Y and Z are three elements in Group 17. X2 has weaker covalent bonds than Y2. X2 has stronger instantaneous dipole–induced dipole interactions between its molecules than Z2. Y2 is a stronger oxidising agent than Z2. What could be X, Y and Z? X Y Z A I Cl Br B I Br Cl C Cl Br I D Br Cl I 9 Use of the Data Booklet is relevant to this question. KCN is used to extract gold, Au, from its ore. Gold dissolves in an aqueous cyanide solution in the presence of air to form Au(CN)2–, which is stable in aqueous solution. 4Au(s) + 8CN–(aq) + O2(g) + 2H2O(l) → 4Au(CN)2–(aq) + 4OH–(aq) What is the minimum volume of air, measured at room temperature and pressure, needed to extract 10 kg of gold from its ore? [You may assume the oxygen content in air to be 20%.] A 305 dm3 B 610 dm3 C 1520 dm3 D 3050 dm3 10 Which reaction represents standard enthalpy change of formation of a substance? A Li+(g) + Cl–(g) → LiCl(s) B 2H2(g) + O2(g) → 2H2O(l) C 2C(g) + 3H2(g) → C2H6(g) D Na(s) + 1 2Cl2(g) → NaCl(s)

© VJC 2024 9729/01/PRELIM/24 [Turn over 5 11 When SOCl2 is added to Ba(OH) 2, a vigorous reaction occurs and the temperature of the solution falls from 25°C to 0°C. What are the correct signs of ΔG and ΔS for this reaction? ΔG ΔS A – + B – – C + – D + + 12 Hydrogen peroxide can be decomposed in the presence of a fixed amount of MnO2 catalyst as follows. 2H2O2 → 2H2O + O2 The rate of the decomposition of hydrogen peroxide can be followed by measuring the time taken for the same volume of oxygen to be produced from a range of hydrogen peroxide concentrations. To find the order of the reaction with respect to hydrogen peroxide, which would be the most suitable graph to plot using the data? A [H2O2] against time B [H2O2] against 1 time C volume of O2 against time D volume of O2 against 1 time

© VJC 2024 9729/01/PRELIM/24 6 13 The Boltzmann distribution for a gas at a constant temperature of T1 is shown. If the temperature of the gas is reduced to T2, the graph changes shape. Which row best describes how the value of n changes at the molecular energies, X and Y respectively? X Y A higher higher B higher lower C lower higher D lower lower 14 SO3 is manufactured from SO2 and O2 in the Contact process. The reaction is exothermic. Which row shows the effect on the equilibrium yield obtained in the Contact process by increasing the temperature and adding a vanadium(V) oxide catalyst? increasing the temperature adding vanadium(V) oxide as catalyst A equilibrium yield decreases equilibrium yield unchanged B equilibrium yield decreases equilibrium yield increases C equilibrium yield increases equilibrium yield unchanged D equilibrium yield increases equilibrium yield increases 15 At a constant total pressure of 1.0 atm, 50% of dinitrogen tetraoxide is dissociated at a temperature of 60°C according to the following equation. N2O4(g) ⇌ 2NO2(g) What is the value of the equilibrium constant, Kp, for this reaction