2023 JVSS Chem Prelims P1

[Turn over JURONGVILLE SECONDARY SCHOOL PRELIMINARY EXAMINATION 2023 Secondary 4 Express STUDENT NAME CLASS INDEX NUMBER CHEMISTRY 6092/01 Paper 1 Multiple Choice 28 August 2023 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, class and index number in the spaces at the top of this page. There are forty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Multiple Choice Answer Sheet. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. A copy of the Periodic Table is printed on page 15. The use of an approved scientific calculator is expected, where appropriate. DO NOT OPEN THE BOOKLET UNTIL YOU ARE TOLD TO DO SO This document consists of 15 printed pages. Setter: Mdm Ethel Chng For Examiner’s Use 40

2 1 A gas is released at point Q in the apparatus shown. Which gas changes the colour of the damp Universal Indicator paper most quickly? A chlorine B hydrogen C hydrogen chloride D oxygen 2 The reaction between aqueous sodium thiosulfate and hydrochloric acid forms a pale yellow precipitate. Na2S2O3(aq) + 2HCl(aq) → 2NaCl(aq) + H2O(l) + SO2(g) + S(s) A student follows the rate of this reaction by measuring the time taken for a cross to disappear. Besides a white tile marked with a cross, what other apparatus would be needed in the student’s experiment? A burette, pipette, stopwatch, thermometer B conical flask, electronic balance, stopwatch C conical flask, measuring cylinder, stopwatch D gas syringe, measuring cylinder, stopwatch 3 The diagram shows the steps for separating a mixture. step 1 step 2 step 3 Which mixture cannot be separated into its components by these steps? A charcoal and sugar B copper(II) sulfate and iron C magnesium nitrate and potassium carbonate D marble chips and sodium chloride point Q damp Universal Indicator paper

3 [Turn over 4 Which observation is not possible for a solid element? A It dissolves in water. B It melts at a fixed temperature. C When heated in air, it forms an oxide. D When it is electrolysed in its molten state, two products are formed. 5 An unknown solid was added to dilute hydrochloric acid. Effervescence was observed and the gas formed a white precipitate in limewater. Addition of aqueous sodium hydroxide to the resulting mixture produced a white precipitate. Upon addition of more aqueous sodium hydroxide, the white precipitate remained insoluble. What could the unknown solid be? A CaCO3 B NaHCO3 C Pb(OH)2 D ZnCO3 6 Chromium has four stable isotopes and forms ions of vari