TMJC 2025 H2 Chem P1 QP

___________________________________________________________________ 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. 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 use of the Answer Sheet very carefully. You are advised to fill in the Answer Sheet as you go along . No additional time will be given for the transfer of answers once the examination has ended. 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 17 printed pages and 1 blank page. Use of the Answer Sheet Ensure you have written your name, class, date and subject on the Answer Sheet. Shade the last four digits of your centre/index number on the Multiple Choice Answer Sheet. (e.g. if your centre/index number is 30541234, shade 1234). Use a 2B pencil to shade your answers on the Answer Sheet; erase any mistakes cleanly. Multiple shaded answers to a question will not be accepted. TAMPINES MERIDIAN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION

2 Tampines Meridian Junior College 2025 JC2 Preliminary Examination H2 Chemistry 1 Use of the Data Booklet is relevant to this question. In an experiment, a sample containing phosphorus and an unknown element A is vapourised, ionised and passed through an electric field as shown below. Given that the extent of deflection for A+ is smaller than P+, which could be the identity of element A? A sulfur B silicon C sodium D nitrogen 2 Use of the Data Booklet is relevant to this question. Which particle contains the largest number of unpaired electrons? A O B Cl– C K+ D Fe 3 In a microwave oven, the microwave produced is absorbed by polar molecules. Which molecules would absorb microwave energy? 1 SO3 2 CH2F2 3 CH3CH2OH A 3 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 beam of P+ and A+ + – P+ A+

3 Tampines Meridian Junior College 2025 JC2 Preliminary Examination H2 Chemistry [Turn over 4 The melting point of potassium is lower than the melting point of magnesium. Which statement is most relevant in explaining the difference? A Potassium ion has a smaller radius than magnesium ion. B Potassium ion has a lower charge than magnesium ion. C Potassium atom contains fewer electrons than magnesium atom. D Potassium atom is heavier than magnesium atom. 5 Which of the following cannot be explained by hydrogen bonding? A The existence of hydrogen–difluoride anion, HF2 – . B The difference in volatility between pentan–1–ol and hexan–1–ol. C The difference in melting point between 2–nitrophenol and 4–nitrophenol. D The relative molecular mass of ethanoic acid in organic solvent is higher than expected.

4 Tampines Meridian Junior College 2025 JC2 Preliminary Examination H2 Chemistry 6 Which diagram correctly describes the behaviour of a fixed mass of an ideal gas? A B C D 7 Use of the Data Booklet is relevant to this question. Sodium percarbonate, (Na2CO3)xy(H2O2), is an oxidising agent used in laundry cleaning products. On acidification, 10.0 cm3 of 0.100 mol dm -3 sodium percarbonate releases 48.0 cm 3 of carbon dioxide at room temperature and pressure. An identical sample, on titration with 0.0500 mol dm -3 KMnO4, requires 24.0 cm 3 before the first pink colour appears. 2 moles of KMnO4 reacts with 5 moles of H2O2. What is the ratio of y/x? A 1 3 B 2 3 C 3 2 D 3 0 V pV constant T 0 V p constant T 0 V pV constant T 0 V p constant T

5 Tampines Meridian Junior College 2025 JC2 Preliminary Examination H2 Chemistry [Turn over 8 G, H and J are three elements found in Period 3 of the Periodic Table. Among the elements in Period 3, • the melting point of G is the highest. • the electrical conductivity of H is the highest. • the melting point of the oxides of J is the highest. Which of the following elements is not represented by G, H or J? A Na B Mg C Al D Si 9 Which equation defines standard enthalpy change of formation correctly? A Na(s) + Cl(g) → NaCl(s) B 2H2(g) + O2(g) → 2H2O(g) C Mg2+(g) + O2–(g) → MgO(s) D H2(g) + S(s) + 2O2(g) → H2SO4(l) 10 Hydrogen can be made from steam. H2O(g) + C(s) H2(g) + CO(g) The Gibbs free energy change of reaction at two different temperatures are shown. At 378 K, G1 = +78 kJ mol–1 At 1300 K, G2 = –58 kJ mol–1 Which row gives the correct signs of H and S for this reaction? H S A ̶ + B ̶ ̶ C + ̶ D + + ⎯⎯ →

6 Tampines Meridian Junior College 2025 JC2 Preliminary Examination H2 Chemistry 11 The equation for the formation of hexaamminecobalt(III), [Co(NH 3)6]3+ complex ion is shown below. 2Co2+ + 12NH3 + H2O2 2[Co(NH3)6]3+ + 2OH− The rate equation is rate = k [Co2+][NH3]3[H2O2]. When the concentration of each reactant is x mol dm-3, the initial rate was found to be y mol dm–3 s–1. What will be the initial rate of the reaction if [Co2+] is 2x, [NH3] is 1 2x and [H2O2] is 2x? A 1 8 y B 1 2 y C 2y D 8y 12 The Michaelis -Menten graph shows how the initial rate of reaction var y as the concentration of the substrate changes for an enzyme-catalysed reaction. Which statement could explain the shape of the graph? A The enzyme is acting as a limiting reagent and is being used up in the reaction. B Substrate molecules inhibit the enzyme at high concentrations which resulted in a constant rate. C The reaction will reach a constant rate when all active sites of the enzyme are occupied. D At high substrate concentration, the order of reaction with respect to substrate is 1 ⎯⎯ →

7 Tampines Meridian Junior College 2025 JC2 Preliminary Examination H2 Chemistry [Turn over 13 A sample of N2O4 was placed in a closed vessel and allowed to reach equilibrium as shown below. N2O4(g) 2NO2(g) H = +57.3 kJ mol-1 When the partial pressure of a sample of N2O4 in a closed vessel was investigated, the following graph was obtained. Which row correctly describes the changes applied to the reaction vessel at times t1 and t2? t1 t2 A Volume decreased Temperature increased B Volume decreased Temperature decreased C Volume increased Temperature increased D Volume increased Temperature decreased 14 10.0 cm3 of 8.00 x 10–3 mol dm–3 HCl(aq) is added to 10.0 cm3 of 6.00 x 10–3 mol dm−3 Ba(OH)2(aq). What is the pH of the resulting solution? A 3.0 B 4.7 C 9.6 D 11.3 15 A saturated solution of Ca(OH)2 is found to have a pH of 12.4 at 25 °C.  

8 Tampines Meridian Junior College 2025 JC2 Preliminary Examination H2 Chemistry Which statements are correct? 1 The Ksp of Ca(OH)2 is 7.92  10–6 mol3 dm–9. 2 The solubility of Ca(OH)2 will increase when aqueous HCl is added. 3 The solubility of Ca(OH)2 would increase when temperature is raised to 40 °C. 4 The pH of the solution would increase when solid Ca(NO3)2 is added. A 1 and 2 only B 2 and 3 only C 3 and 4 only D 1, 2 and 3 only 16 Cortisol is a hormone that plays a critical role in regulating glucose metabolism. After cortisol is reacted with an excess of hydrogen gas in