ADSS Prelim P3

This question paper consists of 13 printed pages including this cover page. ADMIRALTY SECONDARY SCHOOL SUBJECT : Chemistry CODE/PAPER : 6092/3 LEVEL/STREAM : Secondary 4 Express DATE : 19 August 2024 TIME : 0800h – 0950h DURATION : 1 hour 50 minutes Instructions to candidates: Write your name, index number and class on the cover page. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs, tables or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions in the space provided. Candidates are reminded that all quantitative answers should include appropriate units. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. If the degree of accuracy is not specified in the question and if the answer is not exact, give the answer to three significant figures. Give answers in degrees to one decimal place. At the end of the examination, fasten all your work securely together. Chemistry practical notes for this paper are printed on Page 13. DO NOT TURN OVER THIS PAPER UNTIL YOU ARE TOLD TO DO SO. PRELIMINARY EXAMINATION 2024 For Examiner’s Use Paper 3 / 40 NAME: NO: CLASS:

2 1 The reaction of aqueous solutions of alkalis and strong acids is exothermic. H+(aq) + OH–(aq) → H2O(l) You are going to investigate how the temperature changes when different volumes of sulfuric acid and sodium hydroxide are mixed together. Read all the instructions below carefully before starting the experiments in Question 1. Instructions You are going to carry out seven experiments. P is sulfuric acid of unknown concentration. Q is a 1.20 mol/dm3 of sodium hydroxide. (a) Experiment 1  Place a polystyrene (Styrofoam) cup into a 250 cm3 glass beaker.  Put P into a burette and measure 40.00 cm3 of P into the Styrofoam cup. Measure the temperature of P and record the value in the results table provided on page 4.  Use a measuring cylinder to measure 10 cm3 of Q. Pour this volume of Q into the Styrofoam cup containing P. Stir, using the thermometer, and measure the highest temperature reached. Record this temperature in the results table provided on page 4.  Empty the polystyrene cup and rinse it with water. Experiment 2  Place a polystyrene cup into a 250 cm3 glass beaker.  Put P into a burette and measure 35.00 cm3 of P into the Styrofoam cup. Measure the temperature of P and record the value in the results table provided on page 4.  Use a measuring cylinder to measure 15 cm3 of Q. Pour this volume of Q into the Styrofoam cup containing P to make the total volume of the mixture 50 cm3. Stir, using the thermometer, and measure the highest temperature reached. Record this temperature in the results table provided on pa