VJC 2020 H2 Chem Prelim P1 QP

 VJC 2020 9729/01/PRELIM/20 [Turn over VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 24 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, highlighters, glue or correction fluid. Write your name, CT group and VJC exam number on the Answer Sheet in the spaces provided unless this has been done for you. Do not shade your NRIC number. DO NOT WRITE IN ANY BARCODES. 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 choices in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. No mark will 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 12 printed pages.

2  VJC 2020 9729/01/PRELIM/20 1 Which particle contains the most number of unpaired electrons? A Cr B Cu2+ C Mn2+ D Te2– 2 Which ion has less electrons than neutrons and less neutrons than protons? Ion Neutrons Nucleons W– 18 37 X2+ 17 34 Y3+ 16 33 Z3– 16 31 A W– B X2+ C Y3+ D Z3– 3 What is the number of  and  bonds in the molecule, (CN)2CC(CN)2?   A 5 9 B 9 5 C 9 9 D 13 5 4 Which species have the same shape as XeF2? A Cl2O B NO2 C IBr2– D SO32– 5 The Gas Laws can be summarised in the general gas equation pV=nRT, where each symbol has its usual meaning. Which of the following statements are correct? 1 One mole of any ideal gas occupies the same volume under the same conditions of temperature and pressure. 2 The density of an ideal gas at constant pressure is in versely proportional to the temperature. 3 The volume of a given mass of an ideal gas is doubled if its temperature is raised from 25 oC to 50 oC at constant pressure. A 1, 2 and 3 B 1 and 2 only C 1 only D 2 and 3 only

3  VJC 2020 9729/01/PRELIM/20 [Turn over 6 In an experiment, 0.10 g of a volatile liquid P formed 0.025 dm 3 of vapour at 100oC and at 1 bar. What is the relative molecular mass of P? A 0.10 × 373 0.025 × 22.7 B 0.025 × 273 × 22.7 0.10 × 373 C 0.025 × 373 × 22.7 0.10 × 273 D 0.10 × 373 × 22.7 0.025 × 273 7 The graph below shows the variation in the boiling point for 8 consecutive elements in the Periodic Table, all with atomic number less than 21. Which statements are correct? 1 The chloride of E reacts with aqueous sodium hydroxide to give a precipitate which is soluble in excess sodium hydroxide. 2 The oxide of F is neutral in aqueous solution. 3 The oxide of K dissolves readily in water to give a strongly alkaline solution. A 1, 2 and 3 B 1 and 2 only C 1 only D 2 and 3 only E K G F Boiling point H I J L Atomic number

4  VJC 2020 9729/01/PRELIM/20 8 The following graph shows the second ionisation energy of eight consecutive elements. Element P belongs to Period 3 of t he Periodic Table. It has poor electrical conductivity and its chloride has a simple molecular structure. With reference to the graph above, which of the options A, B, C or D, corresponds to the second ionisation energy of element P? 9 Which of the following factors bes t explains why magnesium su lfate has a higher solubility than barium sulfate? A Barium is more electropositive than magnesium. B The charge density of magnesium ions is greater than that of the barium ions. C Magnesium sulfate has numerically larger lattice energy than barium sulfate. D The hydration of barium ions is more exothermic than that of magnesium ions. 10 Due to its radioactive nature, the properties of astatine, At, have to be estimated based on its position in the Periodic Table. Which of the predictions concerning At or its compounds is correct? A Hydrogen astatide has a higher decomposition temperature than hydrogen bromide. B Astatine is a light coloured solid at room temperature. C Silver astatide is soluble in NH3(aq). D Iodine is a stronger oxidising agent than astatine. 11 Which of the following has the most number of atoms? A 24 dm3 of oxygen gas at r.t.p. B 65 g nitrogen gas C 18.75 cm3 of ethanol where the density of ethanol is 0.8 g cm–3 D 254 g of copper metal 2nd IE Atomic number A B C D

5  VJC 2020 9729/01/PRELIM/20 [Turn over 12 Methane was burned in an incorrectly adjusted Bunsen burner. The methane was converted into a mixture of carbon dioxide and carbon monoxide in the ratio 99:1, together with water vapour. What will be the volume of oxygen consumed when y dm3 of methane is burned? A (2y − 0.01y 2 ) dm3 B (2y − 0.01y) dm3 C (y − 0.01y 2 ) dm3 D (y − 0.01y) dm3 13 Hydrogen peroxide reacts with acidified potassium permanganate to produce oxygen gas. 5H2O2 + 2MnO4– + 6H+ → 5Mn2+ + 5O2 + 8H2O Varying volumes of H2O2 of an unknown concentration was reacted with varying volumes of 0.50 mol dm–3 acidified KMnO4 in a series of experiments. The total volume of solutions used in each experiment was 100 cm3. In each experiment, the difference between the highest temperature reached and the initial temperature was calculated, and was plotted against the volume of H2O2 used to produce the graph below. What is the concentration of H 2O2 and the enthalpy change of the reaction per mole of H2O2? [You may assume that specific heat capacity of the solution is 4.2 J g –1 K–1 and density of the solution is 1 g cm–3.] [H2O2] Enthalpy change of reaction A 0.536 mol dm–3 ― 151 kJ mol–1 B 0.214 mol dm–3 ― 378 kJ mol–1 C 0.536 mol dm–3 ― 3210 kJ mol–1 D 0.214 mol dm–3 ― 8030 kJ mol–1 ∆T / ºC Volume of H2O2 / cm3 70 13.5

6  VJC 2020 9729/01/PRELIM/20 14 At 600K, azomethane decomposes according to the following equation. CH3N=NCH3(g) → CH3CH3(g) + N2(g) This reaction is first order with respect to azomethane with a half -life of 20 min. Azomethane was allowed to decompose at an initial pressure of 16 Pa. The pressure of the reaction mixture was measured at various times with the temperature kept constant. What is the time taken for the pressure to reach 30 Pa? A 40 min B 60 min C 80 min D 100 min 15 The reaction between carbon monoxide and chlorine was studied at constant temperature. CO(g) + Cl2(g) ⇌ COCl2(g) H = –113.4 kJ mol–1 The concentrations of the gases in the vessel were followed with time, and the following graph was obtained. Which of the following conclusions can be deduced from the graph? 1 The Kc values at 7.5 min and 15 min are the same. 2 The change in concentration during the period 7.5 min to 10 min was produced by an increase in pressure at constant temperature. 3 The change in concentration during the period 10 min to 15 min was produced by the addition of more chlorine. A 1, 2 and 3 B 2 and 3 only C 2 only D 3 only 0 concentration / mol dm–3 time / min 5 10 15 7.5 CO(g)