2024 Prelims RVHS H2 Chem P3 (QP)

River Valley High School 9729/03/PRELIMS/24 2024 Preliminary Examination [Turn over RIVER VALLEY HIGH SCHOOL JC 2 PRELIMINARY EXAMINATION CANDIDATE NAME CLASS 2 3 J CENTRE NUMBER S INDEX NUMBER H2 CHEMISTRY 9729/03 Paper 3 Free Response 17 September 2024 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your Centre number, index number, class and name on all the work that you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions in the spaces provided on the Question Paper. If additional space is required, you should use the pages at the end of this booklet. The question number must be clearly shown. Section A Answer all the questions. Section B Answer one question. Circle the question number of the question you attempted. A Data Booklet is provided. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Question Number 1 2 3 4 5 units s.f. Total Marks 19 21 20 20 20 80 This document consists of 30 printed pages and 1 blank pages.

2 River Valley High School 9729/03/PRELIMS/24 2024 Preliminary Examination 1 (a) 15.4 g of hydrogen iodide was allowed to partially dissociates into hydrogen and iodine in a 2.00 dm 3 vessel. At equilibrium, 10.2 g of hydrogen iodide was left. 2HI(g) = H2(g) + I2(g) H = +52 kJ mol−1 (i) Explain what is meant by dynamic equilibrium. [1] (ii) Write an expression for the equilibrium constant, Kc, for the dissociation of HI. [1] (iii) Hence, calculate the value of Kc of this reaction. [2] (iv) With reference to position of equilibrium , state and explain the effect of an increase in temperature on the value of Kc. [2] ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ……………………………………………………………………………… ………………………………………………………………………………

3 River Valley High School 9729/03/PRELIMS/24 2024 Preliminary Examination [Turn over (b) Describe and explain the relative basicities of benzylamine, phenylamine and 3-aminobenzonitrile. [4] …………………………………………………………………………………….… ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ……………………………………………………………………………………….

4 River Valley High School 9729/03/PRELIMS/24 2024 Preliminary Examination (c) 3-bromophenylamine reacts with chlorine and iron to form three isomeric products, with the formula C6H6NBrCl. (i) Suggest the structure of the isomer produced in the highest amount. Explain your answer. [1] (ii) Name and describe the mechanism to produce the major product. [3] ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ……………………………………………………………………………….. ………………………………………………………………………………..

5 River Valley High School 9729/03/PRELIMS/24 2024 Preliminary Examination [Turn over (d) The set-up below shows a bomb calorimeter which is used to determine the enthalpy of combustion, Hc, of benzene. In an experiment, 3.00 g of benzene was burned in a bomb calorimeter containing 0.600 kg of water. It was found that the temperature of the water changed from 25.0 °C to 40.0 °C. A layer of black solid was also observed in the bomb calorimeter. (i) Calculate the apparent Hc of benzene from these figures. Ignore the heat capacity of the bomb calorimeter, and use the figure of 4.18 J g−1 K−1 for the specific heat capacity of water. [2] (ii) The bomb calorimeter is typically made of copper. Suggest a reason for doing so. [1] (iii) The theoretical Hc of benzene is reported to be −3268 kJ mol−1. With reference to the observation, comment on the apparent value obtained and suggest a reason for the difference. [2] ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. Benzene

6 River Valley High School 9729/03/PRELIMS/24 2024 Preliminary Examination ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. [Total: 19]

7 River Valley High School 9729/03/PRELIMS/24 2024 Preliminary Examination [Turn over 2 (a) This question is about the oxides of Period 3 elements. (i) Describe the action of water on the oxides of sodium and phosphorus. Write equations for any reactions that occur, and suggest the pH of each solution formed. [2] (ii) The oxides MgO, Al2O3 and SiO2 are all used as refractory materials due to their high melting points. A sample of white powder , containing only one of the oxides above, was provided. Describe simple chemical tests you would carry out on the sample to determine which oxide was present. [2] ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ………………………………………………………………………………. ……………………………………………………………………………….