ACJC Prelim P1 QP

1 © ACJC 2018 9729/01/Prelim/2018 [Turn over ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examination C H E M I S T R Y 9729/01 Higher 2 Paper 1 Multiple Choice 29 August 2018 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 t he 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/18 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2018 Department of Chemistry [Turn over

2 © ACJC 2018 9729/01/Prelim/2018 [Turn over 1 The Basic Oxygen steel-making process is a method of preparing steel from carbon-rich molten pig iron. The process is basic because chemical bases are added to remove impurities. One such impurity is phosphorus pentoxide, P 4O10. Calcium oxide, CaO, is added to remove it and the only product of the reaction is the salt, calcium phosphate, Ca3(PO4)2. How many moles of CaO reacted with one mole of P4O10 in this reaction? A 1 B 1.5 C 3 D 6 2 Two moles of an oxidising agent, XO4− in the presence of excess acid oxidised 96 dm3 of nitrogen dioxide gas at room temperature and pressure to NO3−. What is the number of moles of electrons accepted by one mole of XO4−? A 1 B 2 C 3 D 4 3 Use of the Data Booklet is relevant to this question. The ion T+ contains 28 electrons and 35 neutrons. Which of the following statements about T+ or T is correct? A T and Ga3+ are isoelectronic species. B The elemental form of T can be oxidised by chlorine. C The electronic configuration of T+ ion is 1s2 2s2 2p6 3s2 3p6 3d9 4s1. D The angle of deflection of 27Al3+ is approximately three times that of T+ in an electric field. 4 Which of the following species has a different bond angle from the rest? A ICl3 B SF3+ C ClO3– D N2H4

3 © ACJC 2018 9729/01/Prelim/2018 [Turn over 5 What will happen to the volume of a bubble of air submerged in water under a lake at 10.0 oC and 2.00 atm if it rises to the surface where the temperature is 20.0 oC and the pressure is 1.00 atm? A The volume will increase by a factor of 2.00. B The volume will increase by a factor of 2.07. C The volume will decrease by a factor of 2.00. D The volume will decrease by a factor of 1.93. 6 The graph below shows the variation in the standard enthalpy change of fusion, ∆Hofus for 8 consecutive elements from period 2 to 3 in the periodic table. Standard enthalpy change of fusion is the heat absorbed when one mole of a substance changes its state from solid to liquid under standard conditions. Which of the following statements is true based on the information deduced from the above graph? A The chlorides become more acidic from A to C. B An oxide of E dissolves in water to form an alkaline solution. C Element G has a higher first ionisation energy than element F and H. D Element D has a lower electrical conductivity as compared to element F. A G H ∆Hofus / kJ mol–1 Atomic number B C D E F

4 © ACJC 2018 9729/01/Prelim/2018 [Turn over 7 Some enthalpy changes of combustion are given below. ΔHc / kJ mol−1 CO(g) −283 H2(g) −286 CH3OH(l) −715 What is the enthalpy change of the following reaction, in kJ mol−1? CO(g) + 2H2(g) CH 3OH(l) A −146 B +146 C −140 D +140 8 The reaction of nitrogen monoxide and hydrogen gas 2NO(g) + 2H2(g) N 2(g) + 2H2O(g) is thought to involve the following steps: I NO + NO N 2O2 (fast) II N2O2 + H2 H 2O + N2O (slow) III N2O + H2 N 2 + H2O (fast) Which of the following about the reaction is true? A H2 acts as the catalyst. B The rate equation for the reaction is rate = k[N2O2][H2]. C The overall order of the reaction is 3. D Increasing the concentration of NO does not change the rate of reaction.

5 © ACJC 2018 9729/01/Prelim/2018 [Turn over 9 Hydrogen peroxide reacts with acidified iodide ions liberating iodine according to the equation below: H2O2(aq) + 2H+(aq) + 2I−(aq) I2(aq) + 2H2O(l) The kinetics of this reaction was investigated and it was found to have the following rate equation: rate = k[H2O2] [I−] Two series of experiments were conducted, giving rise to Graph A and Graph B. Graph A Graph B rate of reaction/ mol dm−3 s−1 y x time / s Which of the following shows the correct labelling of the x-axis for Graph A and y-axis for Graph B? x-axis y-axis A [H2O2] [I−] / mol2 dm−6 [H+] / mol dm−3 B [H+] / mol dm−3 [H 2O2] / mol dm−3 C [H2O2] [I−] / mol2 dm−6 [ I−] / mol dm−3 D [H+] / mol dm−3 [I−] / mol dm−3

6 © ACJC 2018 9729/01/Prelim/2018 [Turn over 10 A gaseous dimer, Z, is introduced into an empty gas syringe which has a movable, tightly–fitting plunger. The gas is allowed to expand until equilibrium is reached at a controlled temperature at which 20 % of Z dissociates into its monomer W. Z(g) 2 W(g) Which of the following statements is correct? A The forward reaction is exothermic. B The value of the equilibrium constant, Kp is 0.167 atm. C The pressure inside the syringe at equilibrium will be higher than the atmospheric pressure. D The dissociation of dimer Z will be favoured when the plunger is pushed back into the equilibrium mixture. 11 The acid dissociation constants for the diprotic acid, malonic acid H 2C3H2O4 are Ka1 = 1.5 x 10−3 and Ka2 = 2.0 x 10−6. What is the Kb for HC3H2O4−? A Kw ൈ Ka1 B Kw ൈ Ka2 C Kw / Ka1 D Kw / Ka2 plungergas self–sealing cap for introducing sample syringe oven for controlling equilibrium temperature

7 © ACJC 2018 9729/01/Prelim/2018 [Turn over 12 Hardness in tap water can be determined by titrating a sample against a reagent which forms complex ions with dissolved metal ions. The indicator for this titration requires the pH to be maintained at about 10. Which of the following, in aqueous solution, could be used to maintain the pH at about 10? A 10 cm 3 of 2.0 g dm −3 of sodium hydroxide neutralised by 10 cm 3 of 0.025 mol dm−3 of ethanoic acid B 5 cm 3 of 1.7 g dm −3 of ammonia neutralised by 10 cm 3 of 0.025 mol dm −3 hydrochloric acid C 20 cm3 of 0.05 mol dm −3 of hydrochloric acid neutralised by 5 cm 3 of 1.7 g dm −3 ammonia D 10 cm3 of 0.05 mol dm −3 of ethanoic acid neutralised by 5 cm 3 of 2.0 g dm −3 of sodium hydroxide 13 The solubility product of some sparingly soluble lead compounds are shown below. Which compound will have the lowest concentration of Pb 2+(aq) ions in a saturated solution? compound numerical value of solu