Pure Chem CHS Sec 3 Section A

2024 Test Coverage: Topic 1 (Experimental Design) to Topic 11 (Chemical Bonding & Structure) [Turn Over Name: Index Number: Class: CATHOLIC HIGH SCHOOL End-of-Year Examination Secondary 3 (O-Level Programme) CHEMISTRY 2 October 2024 2 hours 15 minutes Additional Materials: Multiple Choice Answer Sheet 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. There are thirty questions in this Section. 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. 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 8 of Section C. The use of an approved scientific calculator is expected, where appropriate. For examiner’s use only: Total / 30 This document consists of 10 printed pages and 2 blank pages. A

2 Section A 2 The measurements from a chromatography experiment using substance F are shown. The diagram is not drawn to scale. What is the Rf value of F? A 0.55 B 0.61 C 0.90 D 1.64 3 A student accidentally mixed 50 cm3 of water with 50 cm3 of oil. Which method would allow him to obtain 25 cm3 of the oil most easily? A filtration B fractional distillation C simple distillation D use of a separating funnel 1 Which piece of apparatus is used to measure exactly 26.30 cm3 of a liquid? A beaker B burette C measuring cylinder D pipette

3 [Turn Over 4 Which diagram represents a chemical change? 5 Which mixture can be separated by using the set-up below? A aluminium and silicon dioxide B ammonium chloride and naphthalene C iodine and sodium chloride D silicon dioxide and potassium sulfate 6 Bromine gas and air are mixed together to form a homogeneous mixture in a closed vessel. Bromine has a higher density than air. What will be observed after several hours? A The two gases remain mixed. B The two gases separate, a layer of air above bromine gas. C The two gases separate, a layer of bromine gas above air. D There is insufficient information, as it depends on the proportion of each gas in the vessel at the beginning. A B C D heat wet cloth mixture

4 8 The diagram shows the path followed by protons as they pass between two charged plates. They are deflected downwards. What happens to electrons passing between the same two charged plates? A They are deflected downwards by the same extent as the protons. B They are deflected downwards to a smaller extent than the protons. C They are deflected upwards. D They are not deflected at all. 7 A student investigated the diffusion of two gases, NH3 and HCl. Two sets of apparatus were set up as shown at room temperature and pressure. The damp red litmus paper in apparatus 1 changed colour after 30 seconds. How long did it take for the damp blue litmus paper to change colour in apparatus 2? A 21 seconds B 30 seconds C 64 seconds D The damp blue litmus paper would not change colour. protons electrons source of NH3 gas apparatus 1 damp red litmus paper apparatus 2 source of HCl gas damp blue litmus paper

5 [Turn Over 9 What is the chemical formula of ammonium manganate(VII)? A NH4MnO4 B NH4(MnO4)2 C (NH4)2MnO4 D NH4(MnO4)3 10 A covalent molecule Q contains only six shared electrons. What is Q? A Cl2 B CO2 C H2O D NH3 11 The table shows the electronic configuration of the atoms of five elements. element electronic configuration V 1 W 2, 2 X 2, 4 Y 2, 5 Z 2, 8, 1 Which pair of elements can combine to form an ionic compound? A V and Y B V and Z C W and Z D X and Y 12 Which row correctly describes the properties of an ionic compound? melting point / °C electrical conductivity at room temperature and pressure A –38 conducts B –7 does not conduct C 801 does not conduct D 1540 conducts

6 13 Which particles are responsible for the conduction of electricity through iron, graphite and aqueous sodium chloride? iron graphite aqueous sodium chloride A electrons electrons ions B electrons ions electrons C electrons ions ions D ions electrons electrons 14 The diagrams show the structure s of two substances used to make electrical conductors. Which statement correctly describes X and Y? A X is a solid and Y is a liquid. B X is an element and Y is a compound. C Y is harder and stronger than X. D Y is more malleable than X. 15 What is the mass of aluminium in 204 g of aluminium oxide, Al2O3? A 26 g B 27 g C 54 g D 108 g 16 The equation for the complete combustion of ethane, C2H6, is shown. 2C2H6 + 7O2 → 4CO2 + 6H2O Which volume of carbon dioxide, measured at room temperature and pressure, is formed when 0.25 moles of ethane is burnt in excess oxygen? A 6 dm3 B 12 dm3 C 24 dm3 D 48 dm3 X Y

7 [Turn Over 17 An aqueous solution of ethanoic acid, CH3COOH, has a concentration of 2 mol/dm3. Which statement about this solution is correct? A 20 g of ethanoic acid is dissolved in 10 cm3 of water. B 30 g of ethanoic acid is dissolved in 250 cm3 of water. C 60 g of ethanoic acid is dissolved in 1 dm3 of water. D 120 g of ethanoic acid is dissolved in 2 dm3 of water. 18 In an experiment, 310 g of Ca 3(PO4)2 is reacted with 120 g of SiO 2 according to the equation below. 2Ca3(PO4)2 + 6SiO2 → P4O10 + 6CaSiO3 What is the number of moles of P4O10 formed? [Mr: Ca3(PO4)2, 310 ; SiO2, 60] A 0.333 mol B 0.500 mol C 0.667 mol D 1.00 mol 19 Zinc oxide is produced by heating zinc carbonate according to the equation below. ZnCO3(s) → ZnO(s) + CO2(g) What is the percentage yield of zinc oxide if 125 g of zinc carbonate , on heating , produces 65 g of zinc oxide? [Mr: ZnCO3, 125; ZnO, 81] A 48.0% B 52.0% C 64.8% D 80.2% 20 Which has a mass equal to that of 3.01 x 1023 carbon atoms? A a piece of pure graphite containing 1.5 mol of carbon atoms B 0.500 mol of C60 molecules C 6.00 g of impure diamond chips D 12.0 dm3 of carbon dioxide measured at room temperature and pressure

8 21 Which statements about strong and weak acids are always correct? 1 Strong acids ionise to a greater extent in water than weak acids. 2 Strong acids are more concentrated than weak acids. 3 Strong acids have a lower pH than weak acids. A 1 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3 22 Which ionic equation represents the reaction of aqueous sodium hydroxide with dilute nitric acid? A H+ + OH– → H2O B Na+ + NO3– → NaNO3 C Na+ + HNO3 → NaNO3 + H+ D NaOH + H+ → Na+ + H2O 23 Both magnesium carbonate and magnesium oxide react with dilute sulfuric acid. In what way are both reactions the same? A A gas is produced. B An acid is neutralised by a soluble base. C Sulfuric acid is acting as an oxidising agent. D Water is a product. 24 In an accident at a factory, some dilute acid was spilt. Which substance, when added in excess, removes the acid without leaving an alkaline solution? A aqueous ammonia B aqueous sodium hydroxide C solid ammonium nitrate D solid calcium carbon