NYJC 2022 Prelim P1

[Turn Over This document consists of 22 printed pages. NANYANG JUNIOR COLLEGE JC 2 Preliminary Examination Higher 2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 20 Sep 2022 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, CT and NRIC / FIN on the Answer Sheet in the spaces provided. There are thirty questions in 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.

2 H2 Chemistry 9729/01 NYJC J2/2022 PXver 1 Use of the Data Booklet is relevant to this question. Outside the city of Wuwei in China, there is an experimental nuclear reactor that has the potential to generate much smaller amounts of radioactive wastes compared to conventional reactors. In this reactor, isotopes of thorium-232 are irradiated with neutrons to produce isotope Q, which then decompose to form isotope R, and finally to uranium-233 in a three-step radioactive decay reaction shown below. Q RTh 232 90 U 233 92+ n 1 0 Which row describes: • the identity of the element of isotope Q, • the neutron number of isotope R? Q neutron number of R A protactinium 142 B protactinium 141 C thorium 142 D thorium 141 2 Use of the Data Booklet is relevant to this question. Which element has the highest 3rd ionisation energy? A Cd B Rb C Sr D Xe

3 H2 Chemistry 9729/01 NYJC J2/2022 PX [Turn Over 3 Gallium, atomic number 31, is a silvery blue lustrous solid. It has a low melting point of 29.8 °C, becoming silvery white in the liquid state. Analysis of the crystal structure of gallium shows the existence of only covalent Ga2 dimers. Unlike its melting point, gallium has a high boiling point of 2400 °C, similar to other Group 13 elements such as aluminium and indium. Ga2 dimers are not present in liquid gallium. Which statements explain the observed melting and boiling points of Gallium? 1 In the liquid state, gallium exist as cations surrounded by a sea of delocalised valence electrons. 2 In the solid state, there are weak instantaneous dipole -induced dipole interactions between Ga2 dimers. 3 In the solid state, there are strong covalent bonds between Ga atoms. A 1, 2 and 3 B 1 and 2 C 2 and 3 D 1 only 4 At sea level, an inflated bicycle tyre has an internal pressure of 6.8 bar and a temperature of 30 °C. The instructions on the tyre state ‘Safety note: internal pressure must not exceed external pressure by 6 bar.’ The atmospheric pressure is 1 bar. The ty re will burst if the difference between the internal pressure and the external pressure becomes too great. The tyre is placed in the luggage hold of an airliner. The conditions in the luggage hold of this airliner are a temperature of 2 °C and a pressure of 0.47 bar. Assuming the maximum volume of the tyre does not change, which statement explains what will happen to the tyre in the luggage hold? A The tyre will burst as the temperature in the luggage hold will cause the tyre to exceed its maximum allowed temperature. B The tyre will deflate as its internal pressure will be lower than the air pressure in the luggage hold. C The tyre will burst as its internal pressure exceeds the air pressure by the maximum allowed. D The tyre will neither deflate nor burst as the differenc e between its internal pressure and the air pressure is within the maximum allowed.

4 H2 Chemistry 9729/01 NYJC J2/2022 PX 5 An experiment was carried out to determine how the pressure and volume of an ideal gas D vary with different temperature. The graph below was obtained. Which is most likely to be gas E? A 34.02 g of silicon chloride B 12.82 g of sulfur dioxide C 3.100 g of phosphorus D 0.2000 g of hydrogen 6 Which standard enthalpy change is represented by the correct equation? A C(s) + O2(g) → CO2(g) ∆Hf o(CO2) B H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O(l) ∆Hneut o C K+(g) → K+(aq) ∆Hsol o (K+) D S(g) → S2−(g) + 2e− ∆H2ndEA o (S) 7 Which of the following process have different signs for ∆GƟ and ∆SƟ? 1 SO3(l) + H2O(l) → H2SO4(aq) 2 Cl2(g) + 2I−(aq) → I2(aq) + 2Cl−(aq) 3 MgCO3(s) → MgO(s) + CO2(g) A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only pV / Pa m3 T / K gas E gas D 498.6 300 600 0

5 H2 Chemistry 9729/01 NYJC J2/2022 PX [Turn Over 8 The reaction of (1-bromoethyl)benzene with sodium cyanide, NaCN, is investigated in a series of experiments. CH3 Br + CH3 CN + BrCN Experiment CH3 Br / mol dm−3 [CN−] / mol dm−3 I 0.20 2.00 II 2.00 0.20 III 2.00 2.00 It was known that the reaction is first order with respect to (1-bromoethyl)benzene. Which graph shows a correct experimental result and proves the reaction is zero order with respect to sodium cyanide? A B C D Expt II time 2.00 1.00 0.50 t 2t Expt I time 0.20 0.10 0.05 t 2t Expt III time 2.00 1.00 0.50 t 2t Expt III time 2.00 1.00 0.50 t 2t

6 H2 Chemistry 9729/01 NYJC J2/2022 PX 9 In the Haber process, nitrogen and hydrogen is passed over a hot catalyst to produce ammonia. N2(g) + 3H2(g) 2NH3(g) ∆H < 0 Which row correctly describes the operating condition and the possible reason? [POE – position of equilibrium] operating condition reason A 500 atm high pressure to shift POE to the right B 500 °C high temperature to increase rate of reaction C 60 atm low pressure to shift POE to the right D 60 °C low temperature to shift POE to the right 10 The ionic product of water, Kw, is affected by temperature. The table gives the p Kw of pure water at different temperatures. temperature / °C pKw 10 14.5 40 13.5 Solutions of acids and alkalis are prepared by dissolving HCl or NaOH in pure water at 10 °C and at 40 °C. Which solution has the highest ionic concentration? A HCl(aq) at pH 1 at 40 °C. B HCl(aq) at pH 1 at 10 °C C NaOH(aq) at pH 13 at 40 °C. D NaOH(aq) at pH 13 at 10 °C.

7 H2 Chemistry 9729/01 NYJC J2/2022 PX [Turn Over 11 Phosphoric acid is a tribasic acid. H3PO4 H2PO4− + H+ H2PO4− HPO42− + H+ HPO42− PO43− + H+ The graph shows the fraction of each species at different pH. What is the numerical value of Ka2? A 6.3  10−3 B 2.0  10−5 C 6.3  10−8 D 2.0  10−10 0.0 0.2 0.4 0.6 0.8 1.0 0 2 4 6 8 10 12 14 Ka1 Ka2 Ka3 3 pH H2PO4− H3PO4 HPO42− PO43− Fraction of species

8 H2 Chemistry 9729/01 NYJC J2/2022 PX 12 Pyruvic acid is a weak acid that is an important intermediate in many biochemical processes. CH3COCO2H pyruvic acid Which graph best represents the change in pH that occurs when a sample of pyruvic acid is titrated against NaOH(aq)? A B C D 14 7 0 volume of NaOH(aq) pH 14 7 0 volume of NaOH(aq) pH 14 7 0 volume of NaOH(aq) pH 14 7 0 volume of NaOH(aq) pH

9 H2 Chemistry 9729/01 NYJC J2/2022 PX [Turn Over 13 Which of the following compound will rotate plane-polarised light? 1 Br CH3 2 Br Br 3 C CC CH3 H CH3 H A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only

10 H2 Chemistry 9729/01 NYJC J2/2022 PX 14 Low density