2020 ACJC Prelim Paper 1 Qns

1 © ACJC2020 9729/01/Prelim/2020 [Turn over ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examination CHEMISTRY 9729/01 Higher 2 Paper 1 Multiple Choice 16 September 2020 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 this 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/2020 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2020 Department of Chemistry [Turn over

2 © ACJC2020 9729/01/Prelim/2020 [Turn over 1 In July 2020, some households in Singapore reported a Pandan smell in their tap water. This was caused by an organic solvent tetrahydrofuran, THF , which has the following structure. The laboratory found that the concentration of THF in the Pandan smelling water was less than 10 ppb (10 parts per billion) by mass, which was significantly lower than the levels of THF that would cause health concerns. What is the concentration of 10 ppb of THF in mol dm3? Given:  1 billion = 109  density of water = 1.0 g cm3 A 1.39 x 1010 B 1.39 x 107 C 1.56 x 107 D 6.40 x 104 2 Use of the Data Booklet is relevant to this question. The approximate percentage composition of the atmosphere s on four planets are given below. The density of a gas may be defined as the mass of 1 dm3 of the gas. Which mixture of gases has the greatest density? planet gases / % by volume A Jupiter H2 88.8, He 10.2, Ar 1.0 B Neptune H2 80.0, He 19.0, CH4 1.0 C Saturn H2 92.3, He 7.2, CH4 0.5 D Uranus H2 82.5, He 15.2, CH4 2.3 3 Use of the Data Booklet is relevant to this question. An element E can exist in a few oxidation states. 0.01 mol of E2+ is completely reacted with 0.004 mol of acidified KMnO4. What is the final oxidation state of E? A +4 B +3 C 0 D −1

3 © ACJC2020 9729/01/Prelim/2020 [Turn over 4 The successive ionisation energies (IE) of two elements, M and N, are given below. IE / kJ mol–1 1st 2nd 3rd 4th 5th 6th 7th 8th M 550 1065 4138 5500 6910 8760 10230 11800 N 1140 2103 3470 4560 5760 8550 9940 18600 What is the likely formula of the compound that is formed between M and N? A MN B MN2 C M2N D M3N2 5 Which of the following statements best explains why the first ioni sation energy of argon is higher than that of sulfur? A Sulfur is more electronegative than argon. B Argon has a complete octet, while sulfur does not. C The nuclear charge in argon is greater than that in sulfur. D The electron removed from sulfur is unpaired, while that removed from argon is paired. 6 Two glass bulbs X and Y are connected by a closed valve. X contains neon at 20 C at a pressure of 1 x 105 Pa. Y is initially empty, and has three times the volume of X. In an experiment, the valve is opened and the temperature of the whole apparatus is raised to 100 C. What is the final pressure in the system? A 3.18 × 104 Pa B 4.24 × 104 Pa C 1.25 × 105 Pa D 5.09 × 105 Pa 7 Which of the following species is not planar? A XeF4 B ICl3 C PCl4+ D C2Cl4 Y X

4 © ACJC2020 9729/01/Prelim/2020 [Turn over 8 Which diagram best represents the structure of sodium fluoride? A C B D 9 An experiment was carried out to investigate the kinetics of reaction between potassium peroxodisulfate, K2S2O8, and potassium iodide, KI. 2I– + S2O82–  I2 + 2SO42– In each experiment, K2S2O8 and K I solutions are mixed with fixed volumes of Na2S2O3 and starch solutions. The initial concentrations of the K2S2O8 and K I solutions in the mixture and the time taken for the mixture to turn dark blue for the various experimental runs are given below. experiment initial concentration of K2S2O8 / mol dm–3 initial concentration of KI / mol dm–3 time taken to turn dark blue / s 1 0.010 0.020 35 2 0.005 0.020 70 3 0.010 0.004 175 4 0.020 0.040 What is the time taken (in seconds) for the mixture to turn dark blue in experiment 4? A 8.75 B 17.5 C 35 D 140 Na F Na F Na F Na F Na F Na F Na F F– Na+ F– Na+ F– Na+ Na F Na F F– Na+ F– Na+ F– Na+ Na F Na F Na F Na F Na F Na F Na F Na F F– Na+ F– Na+ F– Na+ F– Na+ Na F F– Na+ F– Na+ F– Na+ F– Na+ F– Na+ F– Na+ F– Na+ F– Na+

5 © ACJC2020 9729/01/Prelim/2020 [Turn over 10 In which of the following is the underlined species behaving as a Bronsted -Lowry base? 1 NH4+ + H2O ⇌ NH3 + H3O+ 2 H2SO4 + HNO3 ⇌ HSO4 + H2NO3+ 3 CH3COCH3 + NaNH2 ⇌ CH3OCH2 + Na+ + NH3 A 1 only C 3 only B 1 and 2 only D 1, 2 and 3 only 11 Which of the following statements best explains why AgCl is soluble in aqueous NH3, but AgI is not? A AgCl forms a complex with NH3 but AgI does not. B The solubility product, Ksp, of AgCl is greater than that of AgI. C The Mr of AgI is greater than that of AgCl. D The ionic bonds between Ag+ and I are stronger than the ionic bonds between Ag+ and Cl. 12 In 1893, a new compound Feist’s acid was discovered and found to be optically active. Based on the above information, w hich of the following c ould be the structure s of Feist’s acid? 1 2 3 A 1 only C 1 and 3 only B 1 and 2 only D 1, 2 and 3

6 © ACJC2020 9729/01/Prelim/2020 [Turn over 13 In the presence of ultraviolet light, ethane and bromine react to give a mixture of products. Which compound cannot be present in the mixture of products? A C B D 14 When pent -2-ene is reacted with cold dilute acidified potassium manganate(VII), what will be the major product(s)? A CH3CH2COCOCH3 B CH3CH2CH2CH(OH)CH3 C CH3CH2CH(OH)CH(OH)CH3 D CH3CH2COOH and CH3COOH 15 Cortisol is a hormone involved in the metabolism of fats, proteins and carbohydrates. cortisol How many chiral centres are there in one molecule of cortisol? A 5 B 6 C 7 D 8

7 © ACJC2020 9729/01/Prelim/2020 [Turn over 16 Which alkenes, on reaction with steam at high temperature and pressure in the presence of a phosphoric acid catalyst, could produce an alcohol containing a chiral carbon atom? 1 2 3 A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 17 Halothane is a general inhalation anesthetic used for the induction and maintenance of general anesthesia. halothane Which statement about halothane is correct? A Halothane is highly flammable. B The molecule has two chiral centres. C It may cause the depletion of the ozone layer. D I