2023 YIJC H2 Chem Prelim P4_Suggested Solns

1 YIJC [Turn over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION CANDIDATE NAME CLASS DATE H2 CHEMISTRY 9729/04 Paper 4 Practical Paper 22 August 2023 2 hours 30 minutes Candidates answer on question paper. No Additional Materials are required READ THESE INSTRUCTIONS FIRST Write your name and class in the spaces at the top of this page. Give details of the practical shift and laboratory where appropriate, in the boxes provided . 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 . 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. For Examiner’s use 1 13 2 18 3 12 4 12 Total 55 Shift Laboratory

2 YIJC Answer all the questions in the spaces provided. 1 Determination of enthalpy change of reaction FA 1 is solid sodium hydrogencarbonate, NaHCO3. FA 2 is 2.00 mol dm–3 hydrochloric acid, HCl. equation 1 NaHCO3(s) + HCl(aq)  NaCl(aq) + H2O(l) + CO2(g) ∆Hr(NaHCO3(s)) The molar enthalpy change of reaction of solid sodium hydrogencarbonate wit h hydrochloric acid in equation 1 is the enthalpy change when one mole of solid sodium hydrogencarbonate reacts with excess hydrochloric acid. equation 2 Na2CO3(s) + 2HCl(aq)  2NaCl(aq) + H2O(l) + CO2(g) ∆Hr(Na2CO3(s)) The molar enthalpy change of reaction of sodium carbonate with hydrochloric acid in equati on 2 is the enthalpy change when one mole of sodium carbonate reacts with excess hydrochloric acid. You are to perform an experiment by which you will determine the enthalpy change ∆Hr(NaHCO- 3(s)). You will also determine the enthalpy change ∆Hr(Na2CO3(s)) using the data provided. You will then use your results in a Hess ’ Law calculation to determine the enthalpy change, ∆H, for the reaction of sodium carbonate, Na 2CO3, with water and carbon dioxide to form sodium hydrogencarbonate, NaHCO3, as shown in equation 3. equation 3 Na2CO3(s) + H2O(l) + CO2(g)  2NaHCO3(s) ∆H (a) Follow the instructions below to determine the maximum temperature change when a known mass of solid sodium hydrogencarbonate, FA 1, reacts with hydrochloric acid. In an appropriate format in the space provided below, record  all weighings to an appropriate