2025 H2 Chem Prelim P4 QP_VJC

1 © VJC 2025 9729/04/PRELIM/25 [Turn over CANDIDATE NAME CT GROUP VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 ……………………………………………….………….. …………………………….. CHEMISTRY 9729/04 Paper 4 Practical Candidates answer on the Question Paper. 27 August 2025 2 hours 30 minutes Additional Materials: As listed in the instructions below READ THESE INSTRUCTIONS FIRST Write your name and CT group on all the work you hand in. Give details of the shift and laboratory in the boxes provided. Write in dark blue or black pen. You may use a HB pencil for any diagrams or 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 19 and 20. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. Shift Laboratory For Examiner’s Use 1 / 14 2 / 17 3 / 12 4 / 12 Total / 55 This document consists of 19 printed pages and 1 blank page.

2 © VJC 2025 9729/04/PRELIM/25 Answer all the questions in the spaces provided. 1 Determination of the molar enthalpy change of reaction When zinc powder is added to an aqueous solution of copper(II) ions, a displacement reaction occurs. Cu2+(aq) + Zn(s) → Zn2+(aq) + Cu(s) In this question, you will perform an experiment to determine a value for ΔH. You are provided with: • solid FA 1, zinc • FA 2, containing 0.80 mol dm−3 copper(II) ions (a) (i) You will measure the temperature of the contents in a polystyrene cup at regular time intervals, before and after zinc is added. You will analyse your results graphically to obtain an accurate value of the temperature change caused by the reaction. You will use this value to calculate the heat change, q, for the experiment and hence determine a value for the molar enthalpy change of the reaction, ΔH. In the space provided on page 4, prepares tables in which to record for your experiment: • all weighings to an appropriate level of precision, • all values of temperature, T, to an appropriate level of precision, • all values of time, t, recorded to 0.5 min. It is important that you measure each temperature at the specified time. Procedure 1. Weigh the capped container containing solid FA 1. 2. Place one polystyrene cup inside another polystyrene cup and place both in a glass beaker. 3. Use