Copy of 2024 ANDSS 6092 Prelim P3 QP

This paper consists of 11 printed pages and 1 blank page. O ANDERSON SECONDARY SCHOOL Preliminary Examination 2024 Secondary Four Express CANDIDATE NAME: CLASS: / INDEX NUMBER: CHEMISTRY Paper 3 Practical 6092/03 16 August 2024 1 hour 50 minutes Candidates answer on the Question Paper Additional Materials: Nil READ THESE INSTRUCTIONS FIRST Write your name, class and 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 an HB pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid/tape. 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 page 12. 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 2 3 4 Total

PRELIM 4E CHEM 2024 6092/03 2 1 (a) Read all the instructions carefully before starting the experiments in Question 1. You are provided with salt solution W in a boiling tube. You will carry out tests on W to deduce its identity. You should test and identify any gases evolved. Record all your observations in the table. The volumes given below are approximate and should be estimated rather than measured, unless instructed otherwise. test observations Test 1 Put about 1 cm depth of solution W in a clean test-tube. Add 1 cm depth of aqueous sodium hydroxide. Gently warm the mixture. Test 2 Put about 1 cm depth of solution W in a clean test-tube. Add an equal depth of dilute nitric acid and then add a few drops of aqueous barium nitrate. Test 3 Put about 1 cm depth of solution W in a clean test-tube. Add an equal depth of dilute nitric acid and then add a few drops of aqueous silver nitrate. [4] (b) Deduce the identity of salt W. …………………………………………………………………………………… [2] [Total: 6]

PRELIM 4E CHEM 2024 6092/03 3 2 Malic acid is a carboxylic acid found in apple juice. The equation for the reaction between malic acid, H 2C4H4O5, and potassium hydroxide, KOH, is shown. 2KOH + H2C4H4O5 → K2C4H4O5 + 2H2O The concentration of aqueous malic acid is determined by titration with aqueous potassium hydroxide, KOH(aq). Thymolphthalein is used to determine the end-point of the titration. P is aqueous malic acid. Q is 0.100 mol/dm3 KOH(aq). (a) (i) Put P into the burette. P