ACJC H2 Chem 2021 Prelim Paper 1 Questions - Final

2 ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examination CHEMISTRY 9729/01 Higher 2 Paper 1 Multiple Choice 14 September 2021 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, index number and tutorial class on the Answer Sheet in the spaces provided unless t his 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 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. 9729/01/Prelim/21 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2021 Department of Chemistry [Turn over

2 © ACJC 2021 9729/01/Prelim/2021 [Turn over 1 In an organic synthesis, a 62% yield of product is achieved. Which conversions are consistent with the given information? 1 74 g of butan-2-ol (Mr = 74.0)  44.64 g of butanone (Mr = 72.0) 2 72 g of butanal (Mr = 72.0)  45.88 g of butan-1-ol (Mr = 74.0) 3 56 g of but-2-ene (Mr = 56.0)  37.20 g of ethanoic acid (Mr = 60.0) A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only 2 Use of the Data Booklet is relevant to this question. Sodium percarbonate, x(Na2CO3).y(H2O2) is a chemical that is used in cleaning powders. When dissolved in water, it releases hydrogen peroxide and sodium carbonate, both of which are useful cleaning agents. A sample of 10.0 cm 3 of 0.100 mol dm ‒3 sodium percarbonate requires 20.0 cm 3 of 0.100 mol dm‒3 of acidified KI before the end point of titration is reached. Another identical sample releases 48.0 cm 3 of carbon dioxide at room conditions on reaction with excess acid. What are the values of x and y respectively? x y A 2 1 B 3 2 C 2 3 D 3 1

3 © ACJC 2021 9729/01/Prelim/2021 [Turn over 3 An ion X2+ contains 24 protons. What is the electronic configuration of X3+? A 1s2 2s2 2p6 3s2 3p6 3d3 B 1s2 2s2 2p6 3s2 3p6 3d4 C 1s2 2s2 2p6 3s2 3p6 3d1 4s2 D 1s2 2s2 2p6 3s2 3p6 3d5 4s1 4 A sample of the element calcium was vaporised, ionised and passed through an electric field. It was observed that a beam of 40Ca2+ particles gave an angle of deflection of +4o. Assuming an identical set of experimental conditions, by what angle would a beam of 19F¯ particles be deflected? A +2o B ‒ 2o C +4o D ‒ 4o 5 Use of Data Booklet is relevant to this question. X, Y and Z are isotopes of three different elements. An isotope of Argon has a mass number of 41 and the same number of neutrons in the nucleus as each of the isotopes X, Y and Z. The species Ar, X+, Y2+ and Z3+ all contain the same number of electrons. What are the mass numbers of X, Y and Z? X Y Z A 42 41 40 B 40 41 42 C 44 43 42 D 42 43 44 Source +4o 40Ca2+ + ‒

4 © ACJC 2021 9729/01/Prelim/2021 [Turn over 6 Equimolar amounts of the liquids, water and ethanol, are mixed together at 20 oC. The original intermolecular forces in the pure liquids are disrupted an d weaker intermolecular forces between water and ethanol are made simultaneously. The boiling point of water is 100 oC. The boiling point of ethanol is 78 oC. Which row is correct? initial temperature of mixture boiling point of mixture A above 20 oC above 78 oC B above 20 oC below 78 oC C below 20 oC above 100 oC D below 20 oC below 100 oC 7 The pKa and solubility values of maleic acid and fumaric acid are as follows: maleic acid fumaric acid pKa1 1.94 3.03 pKa2 6.22 4.54 solubility / g per 100g water 78.8 0.49 Which statements are correct? 1 The pKa1 value of maleic acid is less than the pKa1 value of fumaric acid because the conjugate base of maleic acid can form intramolecular hydrogen bond, while that of fumaric acid cannot form such intramolecular hydrogen bond. 2 The pKa1 value of maleic acid is less than the pKa1 value of fumaric acid because maleic acid is much more soluble in water than fumaric acid. 3 The pKa2 value of maleic acid is greater than the pKa2 value of fumaric acid because intramolecular hydrogen bond prevents the conjugate base of maleic acid from deprotonating the second hydrogen atom. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only

5 © ACJC 2021 9729/01/Prelim/2021 [Turn over 8 Which diagram does not describe the behaviour of a fixed mass of an ideal gas? ( = density of the gas, T = temperature measured in K) A C B D 9 Which equation corresponds to the enthalpy change stated? A H2O(l) → 2H(g) + O(g) ∆H = 2 × Bond Energy (O‒H) B ½ Cl2(g) → Cl¯(aq) ∆Hformation(Cl¯(aq)) C CO(g) + ½ O2(g) → CO2(g) ∆Hcombustion(CO2(g)) D Na+(g) → Na+(aq) ∆Hsolution(Na+(g)) 10 Given the following data in kJ mol‒1 enthalpy change of atomisation of Na(s) +107 electron affinity of Cl atom ‒349 enthalpy change of formation of NaCl(s) ‒411 enthalpy change of atomisation of Cl(g) +122 1st IE of Na atom +494 What is the lattice energy of NaCl(s) in kJ mol‒1? A ‒785 B ‒907 C ‒1269 D ‒1483 1/p 0 V constant T pV  0 constant T  0 p constant T 0 p constant V T

6 © ACJC 2021 9729/01/Prelim/2021 [Turn over 11 Trouton’s rule states that the entropy change of vaporisation is about +85 J K−1 mol−1 for various kinds of liquids. Propan-1-ol boils at 371 K and its enthalpy change of vaporisation is +47 kJ mol–1. Which statement is correct? A Entropy change of vaporisation of propan-1-ol cannot be calculated because there is no data on Gibbs free energy change of vaporisation of propan-1-ol. B Entropy change of vaporisation of propan-1-ol is +85 J mol–1 K–1. C Entropy change of vaporisation of propan -1-ol is +127 J mol –1 K–1 which is more positive than +85 J mol –1 K–1 because of the strong hydrogen bonds between molecules. D Entropy change of vaporisation of propan -1-ol is +127 J mol –1 K–1 which is more positive than +85 J mol–1 K–1 because of the weak instantaneous dipole induced dipole attraction between molecules. 12 Ethyl ethanoate undergoes a slow acid-catalysed hydrolysis in water. H+ CH3CO2CH2CH3 + H2O  CH3CO2H + CH3CH2OH The rate equation is found to be rate = k[CH3CO2CH2CH3][H+] When 0.1 mol dm 3 of HCl is reacted with 0.2 mol dm 3 of ethyl ethanoate, the half -life was found to be 62 min. Another reaction was carried out with 0.2 mol dm3 of HCl and 0.2 mol dm3 of ethyl ethanoate. How long does it take for the concentration of ethyl ethanoate to fall to 0.025 mol dm3? A 31 min B 62 min C 93 min D 124 min

7 © ACJC 2021 9729/01/Prelim/2021 [Turn over 13 Sucrase is a digestive enzyme that catalyses the hydrolysis of sucrose to fructose and glucose. In an experiment, the amount of sucrase and the temperature of the reaction mixture is kept constant. Which graph is correct? A C B D 1