2025 RI Prelims H2 Chemistry P1 QP

© Raffles Institution 2025 9729/01/S/25 [Turn Over RAFFLES INSTITUTION 2025 YEAR 6 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 26 September 2025 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not open this question booklet 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 index number in the spaces provided on the Answer Sheet. There are thirty questions in 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 the question booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 13 printed pages and 1 blank page.

© Raffles Institution 2025 9729/01/S/25 [Turn Over 2 1 Use of the Data Booklet is relevant to this question. What are the numbers of electrons and neutrons in the 37Cl+ ion? electrons neutrons A 16 20 B 16 37 C 17 20 D 17 37 2 In two separate experiments, a beam of 17O+ ions and a beam of [16O18O]2– ions, travelling at the same velocity, pass through an electric field as shown. Which statements are correct? 1 The [16O18O]2– ions are deflected to a larger extent than the 17O+ ions. 2 The [16O18O]2– ions are deflected in the opposite direction to the 17O+ ions. 3 The beam of 17O+ ions travels in a straight path towards the negatively charged plate. A 1 and 2 B 1 and 3 C 2 and 3 D 2 only beam of particles + –

© Raffles Institution 2025 9729/01/S/25 [Turn Over 3 3 The table shows the structural formulae of three compounds. compound P Q R structural formulae C C HCl ClH C C ClCl HH CH3CH2CH2CH3 What is the correct order of increasing boiling point of these compounds? A P → Q → R B P → R → Q C R → P → Q D R → Q → P 4 Beryllium is the first member of Group 2 and forms covalent compounds which are said to be electron deficient. In many ways, beryllium resembles aluminium. Which statement regarding compounds of beryllium is correct? A BeF2 acts as a Lewis base when it reacts with NH3 to form the BeF2 • NH3 adduct. B BeF2 • NH3 is a planar molecule. C BeF42– contains two co-ordinate bonds. D The Be F F Be F F n polymer cannot form hydrogen bonds with H2O.

© Raffles Institution 2025 9729/01/S/25 [Turn Over 4 5 Which graph correctly describes the behaviour of a fixed mass of an ideal gas? [T is measured in K.] A B C D 6 Elements X, Y and Z are in Period 3 of the Periodic Table. • X has the highest melting point among all the Period 3 elements. • The chloride of Y has the highest pH among all the Period 3 chlorides when dissolved in water. • Z has the largest ionic radius among all the Period 3 elements. Which statement is correct? A Y has a smaller atomic radius than Z. B Y has a lower electrical conductivity than X. C X has a higher first ionisation energy than Z. D X has a higher electronegativity value than Y. At constant T At constant T pV p 0 1 V p 0 At constant p 1 T density 0 pV T 0 p

© Raffles Institution 2025 9729/01/S/25 [Turn Over 5 7 Which statement about the behaviour of the Group 2 elements from magnesium to barium is correct? A The reducing power decreases. B The reactivity with cold water decreases. C The thermal stability of the metal carbonate increases. D The magnitude of the enthalpy of hydration of the metal ion increases. 8 0.015 mol of NO 2 reacts completely with H 2O to form 0.010 mol of HNO 3 and a nitrogen-containing compound. What could be the identity of the nitrogen-containing compound? A NH3 B NO C HNO2 D N2O3 9 The relative abundances of the isotopes of chromium are given below. 50Cr 52Cr 53Cr 54Cr 4.3% 83.8% 9.5% 2.4% What is the relative atomic mass of chromium calculated from these data? A 51.9 B 52.1 C 52.2 D 52.4 10 Which process is always endothermic? 1 the sublimation of a solid 2 the combustion of a fuel 3 the hydration of a gaseous ion A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3

© Raffles Institution 2025 9729/01/S/25 [Turn Over 6 11 The following table shows the lattice energies for two silver halides. compound theoretical lattice energy / kJ mol−1 experimental lattice energy / kJ mol−1 AgBr −759 −877 AgI –736 –867 Which statement best explains the difference in the deviation of the experimental lattice energy from the theoretical lattice energy? A The difference in electronegativity between Ag and the halogen is greater in AgBr than in AgI. B The interionic distance in AgBr is smaller than that in AgI. C The relative formula mass of AgBr is smaller than that of AgI. D The I− ion is more polarisable than the Br− ion. 12 When heated with oxygen, barium forms barium peroxide, BaO2. The relevant enthalpy changes are shown in the table. enthalpy change / kJ mol−1 Ba(g) → Ba2+(g) + 2e− p Ba2+(g) + O22−(g) → BaO2(s) q Ba(s) → Ba(g) r Ba(s) + O2(g) → BaO2(s) s What is the enthalpy change of the following reaction? O2(g) + 2e− → O22−(g) A s – q + p – r B s – q – p – r C r – s + p + q D r – s + p – q

© Raffles Institution 2025 9729/01/S/25 [Turn Over 7 13 The rates of chemical reactions can often be increased by catalytic action. Which statement about catalysts is correct? A A catalysed reaction has a higher rate constant than the uncatalysed reaction. B In an autocatalytic reaction, the rate of the reaction increases continuously as the reaction progresses. C In a reaction catalysed by a heterogeneous catalyst, the reactant molecules are in the same phase as the catalyst. D In a reaction catalysed by an enzyme, increasing the concentration of the substrate will always result in an increase in the rate of the reaction. 14 The decomposition of a gas, A, undergoes a 3-step mechanism. The rate constants of the three steps are given by k1, k2, and k3 respectively. The overall rate equation for the reaction is given by rate = k1k3[A]2 k3+k2[A] Consider the two statements about the order of reaction for the decomposition of A at constant temperature. 1 At very low pressures of A, the reaction is second order with respect to A. 2 At very high pressures of A, the reaction is first order with respect to A. Which statements are correct? A Both statements are correct. B Neither statement is correct. C Statement 1 only is correct. D Statement 2 only is correct.

© Raffles Institution 2025 9729/01/S/25 [Turn Over 8 15 In a titration experiment, 25.0 cm 3 of a solution of a weak acid, HA, required V cm3 of NaOH solution to neutralise completely. In a separate titration, 1 2V cm3 of the same NaOH solution was added to 25.0 cm3 of the same solution of HA. The pH was measured at this point. How are the value of V and the pH at 1 2 V affected when the experiment was repeated at a higher temperature? value of V pH at 1 2V A decreases decreases B decreases remains the same C remains the same decreases D remains the same remains the same 16 A small amount of solid CuSO4 was added to a saturated solution of PbSO4. Which observation is correct? The Ksp of PbSO4 = 1.8 × 10−8 mol2 dm−6. A No precipitate will form. B A blue precipitate of CuSO4 will form. C A white