ASRJC 2021 J2Prelims H2Chem P1 QP

ASRJC JC2 PRELIMS 2021 9729/01/H2 [Turn over ANDERSON SERANGOON JUNIOR COLLEGE 2021 JC 2 PRELIMINARY EXAMINATION NAME:______________________________ ( ) CLASS: 21 /____ CHEMISTRY 9729/01 Paper 1 Multiple Choice 22 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, class and register number on the Answer Sheet. 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 19 printed pages and 1 blank page. Multiple Choice Answer Sheet Write your name, class and NRIC / FIN number, including the reference letter. Shade the NRIC / FIN number. Exam Title: JC2 PRELIM Exam Details: H2 Chemistry / Paper 1 Date: 22/09/2021

2 ASRJC JC2 PRELIMS 2021 9729/01/H2 1 Two particles, A+ and B3+ are fired with equal velocity into an electric field. The information on two particles are given in the table below. particle number of electrons number of neutrons angle of deflection in an electric field A+ 10 12 2.0° B3+ ? 14 5.1° What is the number of electrons for B3+? A 10 B 11 C 12 D 13 2 A to H are consecutive elements with atomic numbers less than 20. The graph below shows their second ionisation energies (2nd I.E.). Which of the following statements is correct? A The 2nd I.E. of G is lower than that of F due to the inter–electronic repulsion between its paired s electrons. B C exists as diatomic molecules at room temperature. C The compound formed between A and E has a low melting point. D Element B is from Group 17. 0500100015002000250030003500400045005000 ABCDEFGH 2nd I.E. element

3 ASRJC JC2 PRELIMS 2021 9729/01/H2 [Turn over 3 The graph shows the logarithm of the first twelve ionisation energies (I.E.) for element J. What can be deduced about element J from the graph? 1 It can form a compound with oxygen with the formula J2O3. 2 J is likely to have a lower first I.E. than the element preceding it in the same period. 3 It is in the second period (Li to Ne) of the Periodic Table. 4 J has a half–filled p–subshell. A 1, 2 and 3 B 1, 2 and 4 C 1 and 2 only D 3 and 4 only 4 Acrylonitrile, CH2=CHCN is a monomer used to made polyacrylonitrile. Which row correctly describes the number of p bonds and hybridisation in a molecule of acrylonitrile? Number of π bonds Number of sp C atoms Number of sp2 C atoms A 2 2 1 B 3 1 2 C 1 1 2 D 1 2 1 log (I.E.) number of electrons removed

4 ASRJC JC2 PRELIMS 2021 9729/01/H2 5 The mechanism for a certain reaction is given below. Which of the statements are correct? 1 There is a decrease in the bond angle with respect to O atom in step 1. 2 The shape with respect to C atom in bold, changes from tetrahedral to trigonal planar and back to tetrahedral in the mechanism. 3 Dative bond is formed in step 1 and 3. A 1 and 3 B 1 and 2 only C 2 and 3 only D 2 only 6 In which of the following does Statement II give a correct explanation for Statement I? Statement I Statement II 1 Magnesium has a higher melting point than sodium. Magnesium has more delocalised valence electrons which results in stronger metallic bonds. 2 Glycine, H2NCH2COOH, has a higher melting point than 2–hydroxyethanoic acid, HOCH2COOH. Glycine can form more extensive hydrogen bonds than 2–hydroxyethanoic acid. 3 Chloromethane undergoes nucleophilic substitution more easily than fluoromethane. The C–Cl bond in chloromethane is weaker than the C–F bond in fluoromethane. A 2 and 3 only B 1 and 2 only C 1 and 3 only D 1, 2, and 3 step 1 (CH3)3COH HCl+ fast (CH3)3COH2 Cl+ step 2 slow(CH3)3COH2 +(CH3)3C H2O step 3 (CH3)3C fastCl+ (CH3)3CCl

5 ASRJC JC2 PRELIMS 2021 9729/01/H2 [Turn over 7 The amount of carbon monoxide present in air can be determined by its reaction with iodine pentoxide, I2O5, to form carbon dioxide and iodine in the reaction below. 5CO + I2O5 ® I2 + 5CO2 The amount of iodine liberated is then determined by titration with a standard solution of sodium thiosulfate. I2 + 2S2O32– ® S4O62– + 2I– A 100 cm3 sample of polluted air is passed over solid iodine pentoxide and the iodine produced required 20.0 cm3 of 0.20 mol dm–3 of sodium thiosulfate for complete reaction. What is the concentration, in g dm–3, of carbon monoxide present in the sample of polluted air? A 0.100 B 1.12 C 2.80 D 11.2 8 Two glass vessels M and N are connected by a closed valve. M contains helium at 25 oC at a pressure of 1 x 105 Pa. N has been evacuated, and has three times the volume of M. In an experiment, the valve is opened and the whole set–up placed in boiling water at 100 oC. What is the final pressure in the system? A 3.13 × 104 Pa B 3.76 × 104 Pa C 1.00 × 105 Pa D 1.33 × 105 Pa N M

6 ASRJC JC2 PRELIMS 2021 9729/01/H2 9 Which of the following diagrams correctly describes the behavior of a fixed mass of an ideal gas at constant T? A B C D 10 30 cm3 of 0.1 mol dm–3 of sulfuric acid and 40 cm3 of 0.2 mol dm–3 sodium hydroxide were mixed in a Styrofoam cup. Assume that the density and specific heat capacity of the final mixture are 1.0 g cm−3 and 4.2 J g−1 K−1 respectively. What is the temperature change for the reaction given that the standard enthalpy change of neutralisation is −57.3 kJ mol–1? A −1.6 °C B −1.2 °C C +1.2 °C D +1.6 °C p V pV V concentration

7 ASRJC JC2 PRELIMS 2021 9729/01/H2 [Turn over 11 An energy cycle is drawn for the following reaction. The standard enthalpy of formation of BrF3(l) = –301 kJ mol–1. The enthalpy change of BrF3(l) to BrF3(g) is +44 kJ mol–1. What is the average bond energy of the Br–F bond in BrF3? A 152 kJ mol–1 B 159 kJ mol–1 C 202 kJ mol–1 D 404 kJ mol–1

8 ASRJC JC2 PRELIMS 2021 9729/01/H2 12 Methanol can be synthesised from carbon monoxide and hydrogen according to the equation. CO(g) + 2H2(g) CH3OH(g) Higher yield of methanol can be achieved at a lower temperature. Which graph corresponds to the forward process? A B C D DG / kJ mol–1 T / K 0 DG / kJ mol–1 T / K 0 DG / kJ mol–1 T / K 0 DG / kJ mol–1 T / K 0

9 ASRJC JC2 PRELIMS 2021 9729/01/H2 [Turn over 13 The kinetics of the following reaction is investigated under different conditions. The reaction is first order with respect to G. G H The table shows pairs of quantities that were plotted as graphs. Which pairs gave the following graph? y–axis x–axis 1 rate concentration of G 2 half–life of G rate constant 3 concentration of H time A 1 and 2 only B 1 only C 2 and 3 only D 1 and 3 only 0 y-axis x-axis

10 ASRJC JC2 PRELIMS 2021 9729/01/H2 14 The ionic product of water, Kw, is affected by temperature. temperature / °C Kw / mol2 dm-6 0 25 50 1.15 ´ 10-15 1.00 ´ 10-14 5.50 ´ 10-14 What can be deduced from this information? A Only at 25 oC are [H+] and [OH-] equal. B The equilibrium lies more to the left as temperature increases. C The [H+] increases while the [OH-] decreases as temperature increases. D The pH of water at 50 °C is 6.6. 15 Which of the following reactions is the underlined