2019 ASRJC Prelim H2 Chem P1 QP

ASRJC JC2 PRELIMS 2019 9729/01/H2 [Turn over ANDERSON SERANGOON JUNIOR COLLEGE 2019 JC 2 PRELIMINARY EXAMINATIONS CHEMISTRY 9729/01 Higher 2 19 September 2019 Paper 1 Multiple Choice 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 and class on the Answer Sheet in the spaces provided. 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 and 2 blank pages.

2 ASRJC JC2 PRELIMS 2019 9729/01/H2 1 Use of the Data Booklet is relevant to this question. The 68Ge isotope is medically useful because it undergoes a natural radioactive process to give an isotope of a different element, 68Q, which can be used to detect tumours. This transformation of 68Ge occurs when an electron enters the nucleus and changes a prot on into a neutron. Which statement about the composition of an atom of 68Q is correct? A It has 4 electrons in its outer p orbitals. B It has 13 electrons in its outer shell. C It has 37 neutrons. D Its proton number is 32. 2 The successive ionisation energies (IE) of two elements X and Y are given in the table. IE / kJ mol–1 1st 2nd 3rd 4th 5th 6th 7th 8th X 786 1580 3230 4360 16000 20000 23600 29100 Y 1300 3380 5310 7460 8670 9330 22060 27070 What compound is most likely to be formed when X and Y are combined? A ionic, with formula X2Y B ionic, with formula XY2 C covalent, with formula XY2 D covalent, with formula X2Y

3 ASRJC JC2 PRELIMS 2019 9729/01/H2 [Turn over 3 Plants appear green due to the presence of chlorophyll. There are several closely related chlorophylls and the diagram shows a simplified version of one. The various different side–groups are all shown as R. Note that the four N atoms and the Mg ion are planar. Which of the descriptions of the bonds between Mg and the numbered N atoms is most likely to be correct? N atoms numbered 1 and 3 2 and 4 A co–ordinate ionic B co–ordinate  C ionic co–ordinate D  co–ordinate 4 Which molecule has the largest dipole? A B C D

4 ASRJC JC2 PRELIMS 2019 9729/01/H2 5 Which graph best represents the behaviour of a fixed mass of an ideal gas und er the given conditions? ( is the density of the gas) A B C D 6 Which of the following, in aqueous solution, could be used to maintain the pH at about 5? A ammonia and ammonium chloride B ethanoic acid and sodium ethanoate C sodium hydroxide and sodium ethanoate D ethanoic acid only p  constant T 0 p T / K constant V 0 constant p T / °C V 0 V constant T 0

5 ASRJC JC2 PRELIMS 2019 9729/01/H2 [Turn over 7 Values of the ionic product of water, Kw, at different temperatures are given in the table. temperature / °C Kw / mol2 dm–6 15 30 4.50 x 10–15 1.47 x 10–14 What can be deduced from this information? A The association of water molecules by hydrogen bonding increases as temperature increases. B Water is not a neutral liquid at 15 °C. C The concentrations of both H+ and OH− increase as temperature increases. D The ionic dissociation of water is an exothermic reaction. 8 Which property of the halogens increases on descending Group 17? A volatility of the halogens B bond energy of the halogen–halogen bond C ease of oxidation of the halide ion D thermal stability of the hydrogen halide 9 Trichloroisocyanuric acid is commonly used in swimming pools as a disinfectant. The recommended concentration level of the acid is 1.50 mg per litre of water. trichloroisocyanuric acid Mr = 232.5 How many chlorine atoms are present in a 2.50 x 10 6 litre Olympic–sized swimming pool filled with the recommended concentration level of trichloroisocyanuric acid? A 2.91 x 1025 B 2.91 x 1028 C 9.71 x 1024 D 9.71 x 1027

6 ASRJC JC2 PRELIMS 2019 9729/01/H2 10 When 720 cm3 of hydrogen sulfide gas, H2S, is passed through 40 cm 3 of 0.500 mol dm –3 nitric acid, HNO3, a yellow solid of sulfur and a nitrogen–containing compound are formed. The half–equation for oxidation of H2S is shown below. H2S → S + 2H+ + 2e– What could be the nitrogen–containing compound formed from the complete reaction? [All volumes are measured at room temperature and pressure conditions under which H2S is a gas.] A N2 B NO C NO2 D NH3 11 When m g of ethanol was burned under a container of water, it was found that the temperature of 300 g of water rose by T °C. The enthalpy change of combustion of ethanol is –1371 kJ mol −1 and the specific heat capacity of water is 4.2 J g−1 K−1. Which expression below gives the percentage efficiency of this process? A 4.2 46.0 100%300 1371 1000 m T     B 1371 1000 100%300 4.2 46.0 m T     C 300 4.2 ( + 273) 46.0 100%1371 1000 T m     D 300 4.2 46.0 100%1371 1000 T m     thermometer water ethanol (Mr = 46.0)

7 ASRJC JC2 PRELIMS 2019 9729/01/H2 [Turn over 12 The enthalpy change of the thermal decomposition of magnesium carbonate is given as +117 kJ mol–1. MgCO3(s) → MgO(s) + CO2(g) What information, other than that given above, is required to calculate a value for the enthalpy change of formation of MgCO3(s)? A enthalpy change of formation of magnesium oxide and enthalpy change of combustion of carbon B lattice energy of magnesium carbonate and of magnesium oxide C first and second ionisation energies of magnesium D bond energy of the C=O bonds in carbon dioxide 14 The alkaline hydrolysis of 2–chloro–2–methylpropane, (CH3)3CCl, with 0.2 mol dm–3 NaOH produces 2–methylpropan–2–ol, (CH3)3COH. (CH3)3CCl + OH– → (CH3)3COH + Cl– 20% of (CH3)3CCl in a solution of concentration 0.02 mol dm–3 hydrolyses in 5 minutes at a certain temperature. With reference to the overall order of this reaction, what percentage of (CH3)3CCl in a solution of concentration 0.04 mol dm –3 would hydrolyse in 5 minutes at the same temperature? A 10% B 20% C 30% D 40% 13 What will be the signs of the enthalpy and entropy changes when a liquid boils? ∆H ∆S A + + B – + C – – D + –

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