2023 WDL Chem Prelims P1

EXPRESS EXPRESS EXPRESS Name: ………………………………..…..( ) Class: …………. WOODLANDS SECONDARY SCHOOL PRELIMINARY EXAMINATION 2023 Level: Secondary Four Express Marks: 40 Subject: Chemistry Day: Tuesday Paper: 6092/01 Date: 22 August 2023 Duration: 1 hour Time: 1135 – 1235 _____________________________________________________________________ READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and index number on the Answer Sheet in the spaces provided unless this has been done for you. 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. At the end of the examination, submit the OTAS separately from the question paper. DO NOT TURN THE PAGE UNTIL YOU ARE TOLD TO DO SO. This document consists of 20 printed pages.

2 6092/01/Prelim/2023 EXPRESS EXPRESS EXPRESS 1 The diagram below shows the setup for a chemical reaction which produces a gas. The gas is then dried and collected. What could the gas be? A carbon dioxide B hydrogen C oxygen D sulfur dioxide 2 Gore-Tex fabric is a water-resistant and breathable material often used in outdoor sportswear. It can block out rainwater while allowing water vapour from body perspiration to escape. Its structure consists of a few layers of porous membranes, each with pores of different sizes. Which of the following explains how the fabric can be water-resistant and yet breathable? A The pores in the layers are smaller than liquid water droplets and water vapour molecules. B The pores in the layers are bigger than liquid water droplets and water vapour molecules. C The pores in one layer are smaller than liquid water droplets while the pores in other layers are bigger than water vapour molecules. D The pores in one layer are bigger than liquid water droplets while the pores in other layers are smaller than water vapour molecules.

3 6092/01/Prelim/2023 EXPRESS EXPRESS EXPRESS 3 The diagram below shows the solubility curves of 3 salts, P, Q and R over a range of temperatures. P, Q and R were added to separate beakers of water. Which of the following shows the best method of obtaining a solid sample from the mixture? salt P salt Q salt R A crystallisation filtration evaporate to dryness B evaporate to dryness evaporate to dryness filtration C evaporate to dryness crystallisation evaporate to dryness D crystallisation evaporate to dryness filtration

4 6092/01/Prelim/2023 EXPRESS EXPRESS EXPRESS 4 1 An aqueous solution of barium chloride is distilled. 2 What is the temperature shown by the thermometer and what is observed in the distillation flask? thermometer reading/ °C final contents of distillation flask A 96 no residue B 100 white residue C 104 no residue D 106 white residue 5 Which mixture of gases would change the colour of damp red litmus paper? A carbon dioxide and sulfur dioxide B chlorine and ammonia C chlorine and nitrogen dioxide D methane and hydrogen chloride

5 6092/01/Prelim/2023 EXPRESS EXPRESS EXPRESS 6 The graphs below show the mass of precipitate formed when lead(II) nitrate and nitric acid are added successively to solution M and solution N respectively. What are the possible identities of the precipitates formed from solution M and solution N? precipitate from solution M precipitate from solution N A PbCl2 PbCO3 B PbCO3 PbCl2 C Pb(OH)2 PbCO3 D PbSO4 PbCl2 solution M solution N

6 6092/01/Prelim/2023 EXPRESS EXPRESS EXPRESS 7 3 Hydrogen can form both hydrogen, H+, ions and hydride, H−, ions. 4 Which statement about these two ions is correct? 5 A H+ ion has no electrons in its first shell. B H+ ion has more protons than a H− ion. C H− ion has one more electron than a H+ ion. D H− ion is formed when a hydrogen atom loses an electron. 8 The table shows the information about particles P, Q, R and T. particle proton number nucleon number number of electrons P 11 23 10 Q 11 23 11 R 17 35 17 T 17 37 17 Which of the following statements are true about P, Q, R and T? 1 P and Q are particles of the same element. 2 P is a positive ion of atom Q. 3 Q reacts with R to form an ionic compound. 4 R and T are isotopes. 1 A 1 and 3 only B 2 and 4 only C 1, 2 and 3 only D 1, 2, 3 and 4

7 6092/01/Prelim/2023 EXPRESS EXPRESS EXPRESS 9 6 Which statement(s) correctly describe(s) the substance given? statement mixture of magnesium and sulfur magnesium sulfide 1 magnesium and sulfur mix without a chemical reaction magnesium and sulfur combine in a chemical reaction to form magnesium sulfide 2 the mixtures do not have properties of magnesium and sulfur magnesium sulfide has the properties of magnesium and sulfur 3 the ratio of magnesium to sulfur in mixtures can vary the ratio of magnesium to sulfur in magnesium sulfide is always the same A 1 only B 1 and 3 C 2 and 3 D 2 only 10 The diagram shows the structure of an ionic compound. Which of the following is a possible formula for this compound? 7 A CaF2 B MgO C SiO2 D SO2

8 6092/01/Prelim/2023 EXPRESS EXPRESS EXPRESS 11 8 When sucrose is heated, it melts at 192 °C. At this temperature it starts to decompose, and the liquid sucrose turns dark brown. 9 10 Based on the information given, which conclusion is correct? 11 A the covalent bonds are stronger than the intermolecular forces B the intermolecular forces and some covalent bonds are about the same strength C the intermolecular forces are stronger than the covalent bonds D the structure of the solid is a lattice structure 12 Peeling onions often causes tearing of the eyes due to the release of a sulfide compound. Peeling them under running water reduces the problem. Which of the following statements are true about the sulfide compound? 1 It is soluble in water. 2 It is volatile. 3 It is an ionic compound with strong ionic bonds. 4 It is a covalent compound with weak covalent bonds. 12 A 1 and 2 only B 1 and 4 only C 2 and 3 only D 2 and 4 only 13 Solid copper metal, aqueous copper(II) sulfate, solid graphite and molten magnesium chloride can conduct electricity. 13 Which pair can conduct electricity because they both contain mobile electrons? 14 A aqueous copper(II) sulfate and molten magnesium chloride B aqueous copper(II) sulfate and solid copper metal C molten magnesium chloride and solid graphite D solid copper metal and solid graphite 14 An oxide of element X has the formula X2O5. 10.2 g of this oxide contains 5.4 g of X. How many moles are there in 5.4 g of X? A 4.816×25 B 4.816×52 C 10.216×25 D 10.216×52

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