JPJC Prelim 2025 Paper 1 QP H2 Chem

© Jurong Pioneer Junior College [Turn Over NAME CLASS 24S JURONG PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2025 CHEMISTRY 9729/01 Higher 2 Paper 1 Multiple Choice Questions 18 September 2025 1 hour Candidates answer on the Question paper. 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 name, class and exam index number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C or 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. This document consists of 12 printed pages.

2 © Jurong Pioneer Junior College 9729/01/J2 PRELIM EXAM/2025 1 A vessel, at standard temperature and pressure, contains a mixture of 35Cl2 and 37Cl2. The gaseous mixture occupies a volume of 5.7 dm3, and has a mass of 18.0 g. What is the percentage by mass of 35Cl2 in the mixture? A 25 % B 40 % C 60 % D 75 % 2 A stable ion of E has the following properties: • has a noble gas configuration • was obtained by removing electrons from the same orbital Which of the following could be E? A Al B Ca C Cu D S 3 Trifluorooxonium has the formula OF3n+ and its shape is trigonal pyramidal. What is the value of n in trifluorooxonium? A 1 B 2 C 3 D 4 4 A mixture of 10 cm3 of methane and 20 cm3 of ethane was sparked with an excess of oxygen. After cooling, the residual gas was passed through aqueous potassium hydroxide. All gas volumes were measured at the same temperature and pressure. Which volume of gas was absorbed by the alkali? A 20 cm3 B 30 cm3 C 50 cm3 D 100 cm3 5 An ion of metal G can be oxidised by potassium manganate(VII) in acid solution to form GO3−. In an experiment, 1.25  10−3 mol of the ion of G required 37.5 cm 3 of 0.0200 mol dm −3 potassium manganate(VII) for complete reaction. What is the initial oxidation state of the ion of G given that potassium manganate( VII) is reduced to Mn2+? A +1 B +2 C +3 D +4

3 © Jurong Pioneer Junior College 9729/01/J2 PRELIM EXAM/2025 [Turn Over 6 The value of pV is plotted against p for two gases, J and L, where p is the pressure and V is the volume of the gas. Which of the following could be the identities of the gases? Gas J Gas L 1 0.5 mol of N2H2 at 25 C 0.5 mol of H2 at 75 C 2 0.5 mol of NH3 at 25 C 1.5 mol of CH4 at 25 C 3 0.25 mol of H2 at 25 C 0.75 mol of SO2 at 25 C A 1 only B 2 only C 1 and 2 only D 2 and 3 only 7 Three statements about potassium and chlorine and their ions are listed. 1 The atomic radius of a potassium atom is greater than the atomic radius of a chlorine atom. 2 The first ionisation energy of potassium is greater than the first ionisation energy of chlorine. 3 The ionic radius of a potassium ion is greater than the ionic radius of a chloride ion. Which statements are correct? A 1 only B 2 only C 1 and 3 only D 2 and 3 only 3x x pV p Gas L Gas J 0

4 © Jurong Pioneer Junior College 9729/01/J2 PRELIM EXAM/2025 8 A disproportionation reaction is a reaction where a single compound is both oxidised and reduced simultaneously. Bromine reacts with aqueous sodium hydroxide at 25 °C. reaction 1 Br2(aq) + 2NaOH(aq) → NaBr(aq) + NaOBr(aq) + H2O(l) The NaOBr formed is unstable at 25 °C and reacts further. reaction 2 3NaOBr(aq) → 2NaBr(aq) + NaBrO3(aq) In which reactions are disproportionation reactions? A reaction 1 only B reaction 2 only C neither reaction 1 nor reaction 2 D both reaction 1 and reaction 2 9 Which molecule has the largest dipole? A B C D 10 Use of the Data Booklet is relevant to this question. The lattice energies of the compounds, magnesium oxide, magnesium bromide, sodium oxide and sodium bromide, are given in the options below. Which of the following values corresponds to the lattice energy of magnesium bromide?

5 © Jurong Pioneer Junior College 9729/01/J2 PRELIM EXAM/2025 [Turn Over A –752 kJ mol–1 B –2421 kJ mol–1 C –2564 kJ mol–1 D –3790 kJ mol–1 11 Use of Data Booklet is relevant to this question. Nitrous oxide, N2O, commonly known as laughing gas, contains one N=N and one N=O bond per molecule . It burns in ethyne , HCCH, to produce water vapour , carbon dioxide and nitrogen gas as the only products. 5N2O(g) + C2H2 (g) → H2O(g) + 2CO2(g) + 5N2(g) Given that the N =N and N =O bond energies in nitrous oxide are +418 kJ mol –1 and +686 kJ mol–1 respectively, what is the enthalpy change of the above reaction? A +1930 kJ mol–1 B +2260 kJ mol–1 C –1680 kJ mol–1 D –3980 kJ mol–1 12 The average intermolecular forces in water are much stronger than the average intermolecular forces in steam. The average intermolecular forces in ice are slightly stronger than the average intermolecular forces in water. Enthalpy changes are associated with the equilibrium processes shown. H2O(l) = H2O(g) Hb H2O(s) = H2O(l) Hm Which statements are correct? 1 The numerical value of Hb is greater than Hm. 2 Hb and Hm are both negative. 3 The intermolecular forces in ice and water are of the same type. A 1, 2 and 3 B 1 and 2 C 1 and 3 D 3 only 13 The table below gives data for the reaction between N and P at constant temperature. Experiment [N] / mol dm−3 [P] / mol dm−3 Initial rate / mol dm−3 min−1 1 0.003 0.4 1.6  10−3 2 0.006 0.4 1.6  10−3

6 © Jurong Pioneer Junior College 9729/01/J2 PRELIM EXAM/2025 3 0.006 0.8 6.4  10−3 Which statement about the reaction is not correct? A The reaction is a one-step reaction. B The rate constant k has the units of mol‒1 dm3 min−1. C The half−life of N is not constant. D The order of reaction with respect to [P] is 2. 14 Iodine and propanone react according to the following equation. I2(aq) + CH3COCH3(aq) → CH3COCH2I(aq) + HI(aq) If the concentration of propanone is increased, keeping the total reaction volume constant, the initial rate of the reaction also increases. Which of the following statements could be the reason for this? A A greater proportion of collisions are successful at the higher concentration. B The particles are further apart at the higher concentration. C The particles have more energy at the higher concentration. D There are more effective collisions per second between particles at the higher concentration. 15 An alcohol, ROH, reacts reversibly with ethanoic acid to produce an ester. ROH(l) + CH3COOH(l) = CH3COOR(l) + H2O(l) Ho < 0 3.0 mol of ROH, 2.0 mol of CH3COOH and 1.0 mol of water are mixed together and heated to a constant temperature. At this temperature, 1 .5 mol of CH 3COOH is pres ent in the equilibrium mixture. Which statement is correct? A The value of the equilibrium constant is 0.20. B At a lower temperature, the equilibrium amount of CH3COOH is higher than 1.5 mol. C Kc has units of mol-1 dm3. D The equilibrium amount of ester is the same as the equilibrium amount of water. 16 At a temperature T K, 0.60 mol dm–3 of CO and 0.30 mol dm–3 of O2 were introduced into a 5 dm3 vessel and allowed to reach equilibrium. 2 CO (g) + O2 (g) = 2CO2 (g) ∆H < 0

7 © Jurong Pioneer Junior College 9729/01/J2 PRELIM