Woodlands Prelim P1

6092/01/Prelim/24 EXPRESS EXPRESS EXPRESS Name: ........................................................................ ( ) Class: ................ WOODLANDS SECONDARY SCHOOL PRELIMINARY EXAMINATION 2024 Level: Secondary 4 Express Marks: 40 Subject: Pure Chemistry Day: Tuesday Paper: 6092/01 Date: 20 August 2024 Duration: 1 hour Time: 1030 – 1130 hours READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, index number and class on the Answer Sheet in the spaces provided. 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 Answer Sheet. Read the instructions on the Answer Sheet very carefully. 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 20. The use of an approved scientific calculator is expected, where appropriate. DO NOT TURN THE PAGE UNTIL YOU ARE TOLD TO DO SO. This document consists of 19 printed pages and 1 blank page. FOR EXAMINER’S USE Total /40

2 6092/01/Prelim/24 EXPRESS EXPRESS EXPRESS 1 Which row shows the correct drying agent and the corresponding gas that can be collected by upward delivery into a gas jar as shown in the set-up below? drying agent gas collected A anhydrous calcium oxide carbon dioxide B anhydrous calcium oxide ammonia C concentrated sulfuric acid sulfur dioxide D concentrated sulfuric acid chlorine 2 The diagram below shows the apparatus used to obtain pure water from aqueous iron(II) sulfate. Which statement about the separation process is true? A Liquid Q is pale green in colour. B Liquid P becomes lighter in colour. C The temperature at T steadily rises as liquid Q is being collected. D The concentration of iron(II) sulfate in liquid P increases as liquid Q is being collected. gas drying agent

3 6092/01/Prelim/24 EXPRESS EXPRESS EXPRESS 3 A mixture of propane, butane, hydrogen sulfide and carbon dioxide at –30 °C is allowed to cool down gradually to –200 °C. compound melting point / °C boiling point / °C propane –188 –42 butane –135 –1 hydrogen sulfide –85 –51 carbon dioxide –78 –78 Which compound can be solidified first? A butane B carbon dioxide C hydrogen sulfide D propane 4 The apparatus shown is set up using different gases in the beakers. Which gases, when placed into E and F respectively, will cause the water level at X to fall initially? E F A oxygen helium B oxygen nitrogen C helium oxygen D nitrogen helium F E X Y porous pots air air water

4 6092/01/Prelim/24 EXPRESS EXPRESS EXPRESS 5 Two substances P and Q are heating and its changes on heating are recorded below. Which classification is correct? P Q A compound element B element mixture C mixture compound D mixture mixture 6 The table shows details of the particles present in an atom of potassium and in ions of potassium and phosphorous. What are the values of W, X, Y and Z? W X Y Z A 19 20 28 12 B 19 19 34 18 C 20 18 31 18 D 20 20 28 12 formula atomic number nucleon number number of neutrons number of electrons K 19 39 W 19 K+ 19 39 20 X P3– 15 Y 16 Z substance P P, a brown liquid, which separates into a few liquids with different boiling points using fractional distillation. substance Q Q, a colourless liquid, breaks down into hydrogen gas and oxygen gas using electricity.

5 6092/01/Prelim/24 EXPRESS EXPRESS EXPRESS 7 How many electrons are not used in bonding in the molecule below? A 4 B 5 C 6 D 8 8 The diagrams show the structures of two forms of carbon. Which set of data is correct for these two structures? conducts electricity very hard material can be used as a lubricant A S S T B S T S C T S T D T T S 9 Two statements about the structure and properties of metals are given. statement 1: Metals are malleable and have high melting points. statement 2: Metals have mobile electrons in their structure. Which statement is correct? A Both statements are correct and statement 2 explains statement 1. B Both statements are correct but statement 2 does not explain statement 1. C Statement 1 is correct but statement 2 is incorrect. D Statement 2 is correct but statement 1 is incorrect.

6 6092/01/Prelim/24 EXPRESS EXPRESS EXPRESS 10 The equation for the reaction between sodium and water is shown. 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g) What volume of hydrogen is produced when 2.30 g of sodium reacts completely with water? A 1.2 dm3 B 2.4 dm3 C 4.8 dm3 D 9.6 dm3 11 Zinc can be extracted from its compound zinc oxide by heating with carbon. 2ZnO(s) + C(s) → 2Zn(s) + CO2(g) 81.0 g of impure zinc oxide is used to produce 52.0 g of zinc. What is the percentage purity of the zinc oxide used? A 16.0 % B 20.0 % C 64.2 % D 80.0 % 12 Which statement about acids and bases is correct? A All strong acids react with carbonates but all weak acids do not. B The oxides of Group 1 metals are amphoteric. C The pH of 1.0 mol/dm3 ethanoic acid, CH3COOH, is higher than the pH of 1.0 mol/dm3 sulfuric acid, H2SO4. D The pH of 1.0 mol/dm3 nitric acid, HNO3, is lower than the pH of 1.0 mol/dm3 hydrochloric acid, HCl. 13 When a piece of barium is put into sulfuric acid, there is a vigorous reaction but the reaction stops after a short while. What is the explanation for this observation? A An insoluble layer of barium sulfate is formed on barium which prevents further reaction. B Barium has a layer of barium oxide which prevents further reaction with sulfuric acid. C Barium is placed below hydrogen in the reactivity series for metals. D Barium metal is highly resistant to corrosion.

7 6092/01/Prelim/24 EXPRESS EXPRESS EXPRESS 14 A titration was conducted by adding aqueous sodium hydroxide from a burette to hydrochloric acid in a conical flask. The pH of the solution in the flask was recorded during the titration and Graph 1 was obtained. Graph 1 Graph 2 The table below shows some indicators that could be used to identify the endpoint of titrations. For the first titration, the appropriate indicator could be methyl red, bromothymol blue or cresolphthalein. Which indicator is appropriate for the second titration? A methyl orange B methyl red C cresolphthalein D alizarin yellow 15 Which reagent could be used to distinguish dilute nitric acid and dilute hydrochloric acid? A Aqueous ammonia B Aqueous barium chloride C Aqueous silver nitrate D Aqueous sodium carbonate indicator acidic colour range of colour change alkaline colour methyl orange red 3.1 – 4.4 yellow methyl red red 4.4 – 6.2 yellow bromothymol blue yellow 6.0 – 7.6 blue cresolphthalein colourless 8.1 – 9.