2019 ACJC Prelim H2 Chem P1 QP

1 © ACJC 2019 9729/01/Prelim/2019 [Turn over ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examination CHEMISTRY 9729/01 Higher 2 Paper 1 Multiple Choice 18 September 2019 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 18 printed pages. 9729/01/Prelim/19 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2019 Department of Chemistry [Turn over

2 © ACJC 2019 9729/01/Prelim/2019 [Turn over 1 An aqueous mixture of sodium carbonate and sodium hydrogencarbonate was titrated with hydrochloric acid and the pH was recorded. What is a suitable indicator to use for detecting the first end point and the ratio of sodium carbonate to sodium hydrogencarbonate in the mixture? indicator ratio A methyl orange 1:1 B methyl orange 1:2 C thymol blue 1:1 D thymol blue 1:2 2 The most common oxidation state of americium, Am, in aqueous solution is +3. Recently, Cu3+ has been shown to quantitatively oxidise Am3+(aq) in dilute HNO3, while itself is reduced to Cu2+. In an experiment, 20.0 cm 3 of 0.0120 mol dm –3 Am3+(aq) was found to require 24.00 cm3 of 0.0300 mol dm–3 Cu3+ for complete oxidation. What is the formula of the americium-containing species formed? A AmO+ B AmO2+ C AmO22+ D Am2O22+ 0 5 10 15 20 25 30 35 40 pH volume of HCl added / cm3

3 © ACJC 2019 9729/01/Prelim/2019 [Turn over 3 The graph shows the second ionisation energies for ten consecutive elements. Which of the following could be X? A oxygen B fluorine C neon D sodium 4 Which of the following graphs are correct about a fixed amount of an ideal gas? 1 2 3 A 1 and 2 only B 1 and 3 only C 2 and 3 only D all of the above ρ pV T 0 0 p V 0 0 pV T/K 0 0 2nd IE / kJ mol Proton Number −1 X constant T

4 © ACJC 2019 9729/01/Prelim/2019 [Turn over 5 Two single -neck round -bottomed flasks were evacuated and insulated from the surroundings. They were filled separately with gaseous ammonia and gaseous hydrogen chloride at room temperature and connected with a gas tap joint. When the gas tap joint is opened, the two gases are allowed to mix. What is the final pressure of the resultant gas mixture? A more than 3.5 atm but less than 7.0 atm B exactly 3.5 atm C more than 0.5 atm but less than 1.0 atm D exactly 0.5 atm 6 When 1.00 g of ethanol was burned under a beaker of water, it was found that 100 cm 3 of water was heated from 15 ºC to 65 ºC. The process was known to be only 70% efficient. Use these data and values from the Data Booklet to calculate the enthalpy change of combustion of ethanol. A −209 kJ mol–1 B −673 kJ mol–1 C −1373 kJ mol–1 D +1373 kJ mol–1 7 Some standard enthalpy changes are given below. ∆Ho / kJ mol–1 Ca2+(g) + aq ⟶ Ca2+(aq) –1650 Cl–(g) + aq ⟶ Cl–(aq) –364 Ca2+(g) + 2Cl–(g) ⟶ CaCl2(s) –2258 What is the standard enthalpy change of solution of calcium chloride? A +244 kJ mol–1 B –120 kJ mol–1 C –2378 kJ mol–1 D –4636 kJ mol–1 NH3 3.0 atm 250 cm3 HCl 4.0 atm 250 cm3

5 © ACJC 2019 9729/01/Prelim/2019 [Turn over 8 Hydrogen peroxide reacts with acidified iodide ions, liberating iodine. H2O2 + 2I⎺ + 2H+ → I2 + 2H2O In the investigation of this reaction, the following results were obtained. initial concentrations of reactants / mol dm−3 initial rate of formation of iodine / mol dm−3 s−1 [H2O2] [I ⎺ ] [H+] 0.01 0.01 0.10 2.0 x 10−6 0.03 0.01 0.10 6.0 x 10−6 0.03 0.02 0.10 1.2 x 10−5 0.03 0.02 0.20 1.2 x 10−5 Which of the following statements are correct? 1 The rate equation can be written as: rate = k [H2O2][I⎺ ]. 2 The reaction is second order with respect to H+. 3 The value of the rate constant is 0.2. A 1 only B 2 only C 1 and 2 D 1, 2 and 3 9 Phosphorus(V) chloride, PCl5, is a white solid which sublimes at 160 oC. When gaseous phosphorus( V) chloride is heated in a closed container, the following equilibrium is established. PCl5(g) ⇌ PCl3(g) + Cl2(g) ∆H > 0 Rate constant, kb, applies for the backward reaction and equilibrium constant, Kc, applies for the overall process. How will the values of kb and Kc change when the equilibrium is established at a higher temperature than before? kb Kc A increase increase B increase decrease C decrease increase D decrease decrease

6 © ACJC 2019 9729/01/Prelim/2019 [Turn over 10 When gaseous phosphorus( V) chloride is heated in a closed container, the following equilibrium is established. PCl5(g) ⇌ PCl3(g) + Cl2(g) ∆H > 0 0.0200 moles of phosphorus( V) chloride was vaporised completely in a 2.0 dm 3 container. The amount of chlorine gas detected at equilibrium was found to be 0.00400 moles. What is the value of Kc at this temperature? A 1.0  10–3 B 8.0  10–4 C 5.0  10–4 D 4.0  10–4 11 The value of pKw at 40 oC is 13.54. What is the pH of an aqueous solution of 0.05 mol dm–3 Ba(OH)2 at 40 oC? A 12.23 B 12.54 C 12.70 D 13.00 12 In which of the following solutions will solid calcium phosphate, Ca3(PO4)2, be the least soluble at 25 ºC? The numerical value of Ksp of Ca3(PO4)2 is 2.07  1033. A 0.3 mol dm3 Ca(NO3)2 (aq) B 0.3 mol dm3 Na3PO4 (aq) C 0.6 mol dm3 HNO3 (aq) D water

7 © ACJC 2019 9729/01/Prelim/2019 [Turn over 13 A cell diagram is written as follows: Ti(s) │ Ti2+(aq) ║ H2SO4(aq) │SO2(g)│Pt(s) Use relevant data from the Data Booklet, and the following electrode potential Ti2+(aq) + 2e– ⇌ Ti(s) Eo = −1.63V to calculate the standard Gibbs free energy change of the cell in kJ mol−1. A −37 B −157 C −282 D −347 14 Use of the Data Booklet is relevant to this question. The standard reduction potentials of some vanadium species are tabulated below. half-reaction Eo / V V2+(aq) + 2e– V (s) –1.20 V3+(aq) + e– V2+(aq) –0.26 VO2+(aq) + 2H+(aq) + e– V3+(aq) + H2O(l) +0.34 Which of the following metals, when added in excess, will reduce VO2+ to V3+? 1 Sn 2 Zn 3 Pb A 1 and 3 B 2 and 3 C 1 only D 2 only

8 © ACJC 2019 9729/01/Prelim/2019 [Turn over 15 Use of the Data Booklet is relevant to this question. Impure copper containing traces of cobalt, iron and silver was purified via electrolysis. Which cations of the trace metals can be found in solution? A Ag+ only B Ag+ and Fe2+ C Co2+ and Fe2+ D Co3+ and Fe3+ 16 An aqueous transition metal compound, T, was subjected to a series of reactions. Which statements are correct? 1 The anion in S is I–