RVHS Prelim H2 Chemistry P1 QP

River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination [Turn over RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATION CANDIDATE NAME CLASS 2 4 J CENTRE NUMBER S INDEX NUMBER H2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 25 September 2025 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 name, class , centre number and index number on the Answer Sheet in the spaces 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 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 15 printed pages and 1 blank page.

2 River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination 1 The graph below shows the variation in the third ionisation energies for the consecutive elements A to I, all with atomic numbers smaller than 20. The symbols A to I do not represent actual elements. Which of the following can be deduced from the information given? A B2+ is smaller than to C2+. B In an electric field, H+ is deflected to a smaller extent than I+. C The decrease in 3rd ionisation energy from C to D on graph is due to coloumbic repulsion. D G has noble gas electronic configuration. 2 A 50.00 cm3 of a solution of 0.300 mol dm−3 MoOx2− was reduced to Mo3+ using Zn powder. The filtrate required 45.00 cm3 of 0.200 mol dm−3 acidified KMnO4 to revert to its original form of MoOx2−. What is the value of x? A 1 B 2 C 3 D 4

3 River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination [Turn over 3 When 20 cm 3 of a gaseous hydrocarbon was completely burnt in 120 cm³ of oxygen, there is a contraction of 50 cm³. On further treatment with aqueous potassium hydroxide, the volume decreases by 60 cm³. Which could be the formula of the organic compound? All volumes being measured at the room temperature and pressure. A C2H2 B C2H4 C C3H6 D C3H8 4 What is the order of increasing bond angle for four molecules? A BF3 < SF2 < SiF4 < BrF5 B BF3 < SiF4 < SF2 < BrF5 C BrF5 < SiF4 < SF2 < BF3 D BrF5 < SF2 < SiF4 < BF3 5 Nitrogen atoms undergo the same type of hybridisation as carbon atoms. Which species contains the shortest nitrogen-oxygen bond length? A NO2 B NO2+ C NO2− D NO3− 6 The volumes and pressures of a fixed mass of gas are investigated, at different temperatures. The results are plotted on a graph of pV against p at a temperature of T1. The gas behaves as an ideal gas under the conditions chosen. Which plot shows the results for a lower temperature, T2?

4 River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination 7 Use of the Data Booklet is relevant to this question. When 0.86 0 g of ethanol undergoes complete combustion below a beaker containing 300 g of water, the temperature of the water rises by 18 °C. The theoretical enthalpy change of combustion of ethanol is –1367 kJ mol–1. What is the efficiency of the process? A 2% B 7% C 31% D 88% 8 Using the enthalpy changes below, calculate the standard enthalpy change of formation of gaseous hydrogen chloride. enthalpy change/ kJ mol−1 N2(g) + 3H2(g) → 2NH3(g) –92 N2(g) + 4H2(g) + Cl2(g) → 2NH4Cl(s) –629 NH3(g) + HCl(g) → NH4Cl(s) –176 A –46.3 kJ mol−1 B –92.5 kJ mol−1 C –180 kJ mol−1 D –361 kJ mol−1

5 River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination [Turn over 9 Consider the following reactions. reaction 1 2CO2(g) + 3H2O(g) → CH3CH3(g) + 7 2O2(g) H = +1434 kJ mol−1 reaction 2 H2O(l) → H2O(g) H = y kJ mol−1 The standard enthalpy change of combustion of ethane is –1542 kJ mol−1. Which statements are correct? 1 y is +36 2 At 373 K, S for reaction 2 is 𝑦 373 kJ mol−1 K−1. 3 Reaction 1 is spontaneous only at high temperatures. A 1 and 2 only B 1 and 3 only C 2 and 3 only D 2 only 10 The half –life of a radioactive isotope P is twice that of another radioactive isotope Q. In a sample of rock, it is found that the number of atoms of Q is 4 times that of P. What will be the ratio of the number of atoms of P to the number of atoms of Q in the rock after two half–lives of P? A B C D 1 16 1 4 1 2 1

6 River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination 11 The distribution of the number of molecules with energy E is given in the sketch for two temperatures, T1 and T2. The letters P, Q, R refer to the separate and differently shaded areas. The activation energy is marked on the energy axis. Which expression gives the fraction of the molecules present which have at least the activation energy at the higher temperature T2? A B C D 12 Sulfur is converted to SF6 by fluorine, to SCl2 by chlorine and to S2Br2 by bromine. Which trend does this information best provide evidence for? A bond energy: Cl2 > Br2 > F2 B electronegativity: F > Cl > Br C first ionisation energy: F > Cl > Br D oxidising ability: F2 > Cl2 > Br2 Q P QR P + QR PQ + + QR P Q R + ++ region P region Q region R Legend Number of molecules with energy E T1 T2 energy E activation energy T2 > T1

7 River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination [Turn over 13 Methanol can be synthesised from carbon monoxide and hydrogen according to the equation. CO(g) + 2H2(g)  CH3OH(g) A higher yield of methanol can be achieved at a lower temperature. Which graph corresponds to the forward process? A B C D G / kJ mol–1 T / K 0 G / kJ mol–1 T / K 0 G / kJ mol–1 T / K 0 G / kJ mol–1 T / K 0

8 River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination 14 1.00 mol of N2O4 and 0.200 mol of NO2 are added to a sealed vessel of fixed volume at 298 K. When the system reaches equilibrium, 0.680 mol of NO2 is present in the vessel. N2O4(g) ⇌ 2NO2(g) Which statement about this equilibrium is correct? A 0.240 mol of N2O4 is present at equilibrium. B The value for the equilibrium constant, Kc, is 0.608. C The pressure in the vessel at equilibrium is the same as the pressure before the reaction started. D The pressure in the vessel at equilibrium is higher than the pressure before the reaction started. 15 The value of the ionic product of water, Kw, varies with temperature. Which statement is correct? A The ionic dissociation of water is an exothermic process. B The ionic dissociation of water increases 100 times between 25 C and 62 C. C Water becomes acidic as temperature increases. D [OH−] increases as temperature increases.

9 River Valley High School 9729/01/PRELIMS/25 2025 Preliminary Examination [Turn over 16 Pyruvic acid, CH3COCO2H, and acetylsalicylic acid, C 6H5COOH, are weak acids. Both acids dissociate in aqueous solutions as follow s, where  is the degree of dissociation. RCOOH  RCOO− + H+ The dissociation constants, Ka of CH3COCO2H and Ka of C6H5COOH, are given in the table below. CH3COCO2H C6H5COOH Dissociation constant/ mol dm−3 1.4 × 10−4 3.4 × 10−4 Which statement is correct? 1 The pH of 1 mol dm−3 of CH3COCO2H is lower than that of 1 mol dm−3 of C6H5COOH. 2 The value of dissociation constant in terms of initial concentration C and degree