2023_TJC_H2Chemistry_P4_Ans

9729 / TJC Prelims / 2023 DO NOT WRITE IN THIS MARGIN [Turn over TEMASEK JUNIOR COLLEGE 2023 JC2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME ANSWER CIVICS GROUP / CENTRE NUMBER S INDEX NUMBER Chemistry 9729/04 Paper 4 Practical 28 August 2023 2 hours 30 minutes Candidates answer on the Question Paper. READ THESE INSTRUCTIONS FIRST Write your centre number, index number, name and CG 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 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. This document consists of 18 printed pages and 2 blank page. For Examiner’s Use 1 2 3 4 Total / 55 Shift Laboratory

2 DO NOT WRITE IN THIS MARGIN 9729 / TJC Prelims / 2023 DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN Answer all the questions in the spaces provided. 1 In this experiment you are to determine the relative formula mass of an iron(II) salt by titration with potassium manganate(VII). FA 1 is the iron (II) salt. FA 2 is 0.0100 mol dm3 potassium manganate(VII), KMnO4. FA 3 is 1.0 mol dm–3 sulfuric acid, H2SO4. Method (a) Preparing a solution of FA 1 1. Weigh accurately about 4.0 g of FA 1 into the plastic vial labelled FA 1 and record the mass in the space below. 2. Transfer all the weighed FA 1 into a 250 cm3 beaker. 3. Use a measuring cylinder to add approximately 100 cm3 of FA 3 to the beaker. Stir until all the solid has dissolved. 4. Transfer the solution into the 250 cm3 volumetric (graduated) flask labelled FA 4. 5. Wash out the beaker thoroughly using distilled water and add the washings to the volumetric flask. Make the solution up to the mark using distilled water. 6. Shake the flask thoroughly to mix the solution before using it for your titrations. Label this solution of the iron(II) salt as FA 4. Mass of plastic vial/g 6.01 Mass of plastic vial and FA 1/g 9.91 Mass of plastic vial and residue/g 6.01 Mass of FA 1 used/g 3.90 [2] [1] Table with correct headings and units [1] All readings to 2 or 3 d.p (b) Titration of FA 4 against FA 2 1. Fill the burette with FA 2. Retain the burette containing FA 2 for Q2. 2. Pipette 25.0 cm3 of FA 4 into a conical flask. 3. Use a measuring cylinder t