JPJC Prelim 2025 Paper 4 QP_H2 Chem

© Jurong Pioneer Junior College [Turn Over NAME CLASS 24S JURONG PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2025 CHEMISTRY 9729/04 Higher 2 Paper 4 Practical 26 August 2025 2 hours 30 minutes Candidates answer on the Question paper. Additional Materials: As listed in the Confidential Instructions READ THESE INSTRUCTIONS FIRST Write your name, class and exam index number on all the work you hand in. Give details of the practical shift and laboratory where appropriate, in the boxes provided. Write in dark blue or black pen. You may use a HB pencil for any diagrams, graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. Qualitative Analysis Notes are printed on pages 23 and 24. Shift At the end of the examination, fasten all your work securely together. Laboratory The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 11 2 19 3 13 4 12 Total 55 This document consists of 23 printed pages and 1 blank page.

2 © Jurong Pioneer Junior College 9729/04/J2 PRELIMINARY EXAM/2025 Answer all the questions in the spaces provided. 1 Determination of the enthalpy change for the reaction between NaOH and CO2 For Examiner’s Use In this experiment you will determine the enthalpy change, H1, for the reaction shown in equation 1. equation 1 NaOH(aq) + CO2(g) → NaHCO3(aq) H1 Sodium hydrogen carbonate and sodium hydroxide each react with sulfuric acid as shown in equations 2 and 3. equation 2 2NaHCO3(s) + H2SO4(aq) → Na2SO4(aq) + 2H2O(l) + 2CO2(g) H2 equation 3 2NaOH(aq) + H2SO4(aq) → Na2SO4(aq) + 2H2O(l) H3 You will determine the values of H2 and H3 and use Hess’s law to calculate H1. (a) (i) Reaction of sodium hydrogen carbonate with sulfuric acid FA 1 is solid sodium hydrogen carbonate FA 2 is 1.0 mol dm–3 sulfuric acid, H2SO4 In this experiment, you will measure the initial temperature of sulfuric acid in a polystyrene cup. After a sample of sodium hydrogen carbonate is added to sulfuric acid, which is in excess, you will measure the minimum temperature reached in the experiment . You will then determine the temperature fall caused by the reaction. In the space provided on page 3, prepare tables in which to record for the experiment: • all weighings to an appropriate level of precision, • all required temperature measurements to an appropriate level of precision. Procedure: 1. Weigh the capped bottle containing solid FA 1. 2. Using a mea