2022 TJC Prelims H2 Paper 1 MCQ QP

9729 / TJC Prelims / 2022 [Turn over TEMASEK JUNIOR COLLEGE 2022 JC2 PRELIMINARY EXAMINATION Higher 2 Chemistry 9729/01 Paper 1 Multiple Choice 16 September 2022 1 hour Additional Materials: Multiple Choice Answer Sheet (OMS) Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C, D. Choose the one you consider correct and record your choice in soft pencil on the separate OMS. Read the instructions on the OMS very carefully. Write your name & Civics Group on the OMS. Shade your index number in the appropriate boxes. 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 16 printed pages. Write your name and Civics Group Index number (refer to entry proof)

2 9729 / TJC Prelims / 2022 1 Use of the Data Booklet is relevant to this question. Atoms or ions that contain the same number of neutrons are isotonic. Which of the following pairs of ions fulfil both criteria below? • The two ions are isotonic. • The first ion deflects more than the second ion when passed through an electric field. A 35Cl–, 31P– B 31P–, 31P3– C 31P3–, 32P2– D 31P3–, 32S2– 2 The variation in the third ionisation energy of six consecutive elements in the Periodic Table is shown in the graph. Which of these elements is a Group 15 element? proton number 3rd ionisation energy / kJ mol−1 A B C D

3 9729 / TJC Prelims / 2022 [Turn over 3 Which group of particles is in order of increasing first ionisation energy? 1 Ga Ge As 2 As Se Br 3 Se Br Kr 4 P As Sb A 1 and 3 B 2 and 4 C 2 and 3 D 1 and 4 4 Carbon forms double bonds with oxygen, and with two other Group 16 elements, Y and Z. In the molecules CO 2, COY and COZ, the polarities of these double bonds do not necessarily cancel. overall polarity of molecule CO2 0 COY 0.71 COZ 0.73 Which factor best accounts for these observations? A The C=O bond is the least polar, while the C=Z bond is the most polar. B Electronegativity increases in the order: Z < Y < O C The C=O, C=Y and C=Z bonds are all polar. D Bond length increases in the order: C=O < C=Y < C=Z 5 Which of the following best describes the change in bond angle when SO2 is converted to SO3? A Decreases to 107o B Increases to 107o C Decreases to 120o D Increases to 120o

4 9729 / TJC Prelims / 2022 6 Which graph correctly describes the behaviour of fixed masses of the ideal gases L and M where the number of moles of L is greater than number of moles of M? A B C D 7 X, Y and Z are elements in Period 3 of the Periodic Table. The table below shows the changes in pH when compounds of these elements are added to water. element change in pH of solution when oxide of element is added to water change in pH of solution when chloride of element is added to water X increases no change Y decreases decreases Z no change decreases What could be the identities of X, Y and Z? X Y Z A Na Al Mg B Na P Al C Si P Al D P Na Si

5 9729 / TJC Prelims / 2022 [Turn over 8 Which of the following statements about Group 2 elements is correct? A Solubility of hydroxides decreases down the group. B Covalent character of chlorides increases down the group. C Thermal stability of carbonates increases down the group. D Electrode potential, EƟ(M2+/M), becomes more positive down the group. 9 Which of the following statements about the Group 17 elements and compounds is incorrect? A When aqueous sodium chloride is added to aqueous bromine, the orange solution is decolourised. B When aqueous silver nitrate is added to aqueous sodium chloride followed by nitric acid, a white precipitate remains. C When aqueous chlorine is added to excess sodium thiosulfate, followed by barium nitrate, a white precipitate is formed. D When chlorine gas is bubbled through potassium iodide, the solution turns brown. 10 A 15 cm 3 mixture of carbon monoxide and methane was mixed with excess oxygen and exploded. CH4 + 2O2 → CO2 + 2H2O CO + 1 2 O2 → CO2 There was a contraction in volume of 15 cm 3 at room temperature and pressure after the reaction. What is the percentage by volume of methane in the mixture? A 33 % B 50 % C 60 % D 75 %

6 9729 / TJC Prelims / 2022 11 Magnesium reacts readily with dilute hydrochloric acid to form magnesium chloride and hydrogen. Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) The standard enthalpy change for this reaction can be measured in the laboratory. What further information is needed in order to calculate the standard enthalpy change of formation of magnesium chloride? 1 Hf for HCl(aq) 2 lattice energy of MgCl2 3 enthalpy change of solution of MgCl2 A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 12 2A + 2B → A2B2 The mechanism for the above reaction involves the following steps. 2A ⇌ C fast B + C → D slow B + D → A2B2 fast Based on the information, what is the rate equation for this reaction? A rate = k [A]2 [B]2 B rate = k [B] [C] C rate = k [A]2 [B] D rate = k [A] [B]2

7 9729 / TJC Prelims / 2022 [Turn over 13 Consider the reaction V + W + X ⎯⎯→ products Two separate experiments were carried out using 1.0 mol dm−3 and 2.0 mol dm −3 of V respectively. A graph of the variation of the concentration of W with time is plotted. Which of the following statements can be determined from the above information? 1 The reaction is first order with respect to V. 2 The reaction is zero order with respect to W. 3 The reaction is first order with respect to X. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only [W] / mol dm–3 0.10 10 20 time / min [V] =1.0 mol dm–3 [V] =2.0 mol dm–3 0

8 9729 / TJC Prelims / 2022 14 When 0.1 mol of bismuth chloride is added to 2 dm3 of water, it reacts to form 0.02 mol of white precipitate of bismuth oxychloride and a solution of hydrochloric acid. The equation for the reaction is as follows: BiCl3(aq) + H2O(l) ⇌ BiOCl(s) + 2HCl(aq) What is the correct expression for the equilibrium constant Kc? A (2 × 0.02)2 0.08 B (0.02)(2 × 0.02)2 0.08 C (0.02 2 ) (2 × 0.02 2 ) 2 0.08 2 D (2 × 0.02 2 ) 2 0.08 2 15 The enthalpy change of dissociation of ethanoic acid in water is +1.0 kJ mol–1. Which correctly describes the value of acid dissociation constant and degree of dissociation when temperature increases? acid dissociation constant degree of dissociation A increase remain constant B increase increase C decrease remain constant D decrease increase

9 9729 / TJC Prelims / 2022 [Turn over 16 The numerical value of the solubility product of copper(I) iodide is 1.27  10–12. Given that HI is a strong acid, which diagram shows how the solubility product of CuI will vary with pH at constant temperature? A B C D 17 Buta-1,3-diene, CH2=CH-CH=CH2, reacts completely with two moles of hydrogen chloride. Which of the following about the products formed is correct? No. of constitutional isomers No. of products that are secondary chloroalkanes A 2 1 B 3 1 C 3 2 D 4 2

10 9729 / TJC Prelims / 2022 18 Both cyclohexene and benzene react with bromine, but under different conditions. Cyclohexene reacts readily with liquid bromine while benzene requires a catalyst before a reaction with bromine can occur. Which of the following explains why cyclohexene is more reactive than benzene? A The local