Copy of CHS 2024 S4 OP Prelim Paper 2 Section A

[Turn Over Name: Index Number: Class: CATHOLIC HIGH SCHOOL Preliminary Examination Secondary 4 ‘O’ Level Programme CHEMISTRY 6092/02 Paper 2 20 August 2024 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, index number and class on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided. The number of marks is given in brackets [ ] at the end of each question or part question. The use of an approved scientific calculator is expected, where appropriate. A maximum of 1 mark will be deducted from your total mark for failure to show your working with clear statements in calculations and misuse of units and/or significant figures, i.e. failure to quote units where necessary, the inclusion of units in quantities defined as ratios or quoting answers to an inappropriate number of significant figures. For examiner’s use only: Section A / 70 working / units / significant figures  −1 if checked This document consists of 18 printed pages and 2 blank pages. A

2 Section A Answer all questions. 1 Some chemical and word equations, A to J, are shown. A glucose → ethanol + carbon dioxide B HNO3 + NaOH → NaNO3 + H2O C water → hydrogen + oxygen D C12H26 → C8H18 + C4H8 E ethanoic acid + ethanol ⇌ ethyl ethanoate + water F ethene + steam → ethanol G 2CH4 + 3O2 → 2CO + 4H2O H C2H6 + Cl2 → C2H5Cl + HCl I C6H12O6 + 6O2 → 6CO2 + 6H2O J 2HCl + Pb(NO3)2 → PbCl2 + 2HNO3 Use the equations to answer the questions that follow. Each equation may be used once, more than once, or not at all. Write down the letter, A to J, for the equation which represents: (a) cracking ……………………………………………….………………….………………………..…….. [1] (b) neutralisation ………………………………………………………………..….…………………...…..…….. [1] (c) precipitation …………………………………………………………………...…………………...…..…….. [1] (d) respiration ……………………………………………………………….………..……………...…..…….. [1] (e) substitution ……………………………………………………………….………………..……...…..…….. [1] [Total: 5]

3 [Turn Over 2 Table 2.1 shows the structural formula of monomers, structure of repeat unit of polymers and type of reaction used to form polymers A and B. Complete the table by filling in the missing information. Table 2.1 polymer structural formula of monomer(s) structure of repeat unit of polymer type of reaction used to form polymer A CH3CH=CH2 ……………………. B HOOC–(CH2)4–COOH H2N−(CH2)6−NH2 ……………………. [4] [Total: 4]

4 3 Car engines are adjusted to work in a particular ratio of air to fuel. The amount of air that is mixed with the fuel affects the temperature of the engine, the amount of pollutant gases that form and how efficiently the catalytic converter works. Table 3.1 shows some information about lean burn engines compared to normal car engines. Table 3.1 type of engine air to fuel ratio operating temperature concentration of carbon monoxide in exhaust gases concentration of nitrogen oxides in exhaust gases normal lower higher higher higher lean burn higher lower lower lower (a) Suggest why lean burn engines produce a lower concentration of nitrogen oxides. ………………………………………………………………..……………………………………….. ……………………………………………………………………………………………………... [1] (b) Suggest why lean burn engines produce a lower concentration of carbon monoxide. ………………………………………………………………..……………………………………….. ……………………………………………………………………………………………………... [1] (c) Nitrogen oxides are removed from car exhaust emissions by catalytic converters. In a catalytic converter, nitrogen monoxide reacts with carbon monoxide. (i) Write a chemical equation for this reaction. ……………………………………………………………………………..…….…………. [1]

5 [Turn Over (ii) Without a catalyst, the reaction between carbon monoxide and nitrogen monoxide is slow. Use ideas about energy and collisions to explain why carbon monoxide and nitrogen monoxide react faster in a catalytic converter. ……………………………….…………………………………………………………….……. ……………………………………………………………………………………………..……. ……………………………………………………………………………………………..……. ………………………………………………………………………………………….….……. ………………………………………………………………………………………….….……. ………………………………………………………………………………………….….……. ………………..……………………………………………………………..………………. [3] [Total: 6]

6 4 This question is about making salts. (a) Copper(II) nitrate can be prepared by reacting excess copper(II) oxide with dilute nitric acid. (i) Describe how pure, dry crystals of copper( II) nitrate is obtained after excess copper(II) oxide is added to dilute nitric acid. ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………………………… ………………………………………………………………………………..………….... [3] (ii) Explain why copper cannot be used to prepare copper(II) nitrate. ………………………………………………………………………………………………… ………………………………………………………………………………..………….... [1] (b) Sodium sulfate is used in the manufacture of laundry detergents. (i) State the formulae, with state symbols, of the reagents used to prepare sodium sulfate. reagent 1 ………………………………………………………………………..…………… reagent 2 …………………………………..………………………………..………….... [2] (ii) Explain why the method described in (a) cannot be used to prepare pure sodium sulfate. ………………………………………………………………………………………………… ………………………………………………………………………………..………….... [1] [Total: 7]

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8 5 (a) Fig. 5.1 shows an experiment in which steam was passed over 5.6 g of hot iron filings. The products of the reaction are iron oxide, Fe3O4, and a gas. Fig. 5.1 (i) State the gas produced and describe a test to identify the gas. ……………………………………………………………………………………..……………. …………………………………………………………………………………..………………. ………………………………………………………………………………….……………. [2] (ii) Describe and explain the change in mass of the solid during the experiment. ……………………………………………………………..……………………………………. ……………………………………………………………..……………………………………. ……………………………………………………………..…………………..……………. [2] (iii) The experiment is repeated using the same amount of magnesium and again using the same amount of lead. Predict the order of change in mass of the solid for iron, magnesium and lead, starting with the metal with the least change in mass. Explain your reasoning in words or by means of a calculation. order of change in mass ……….………………………………………………………..……. reasoning ……………...……..…………………………………………………………..……. …………………………………………………………………………………………..………. ………………………………………………………………………………..……..………. [3] iron filings

9 [Turn Over (b) The Statue of Liberty in New York is made from an iron frame covered with copper plates. In 2004, work had to be carried out to stop the iron frame from rusting. The iron frame was rusting much faster than normal where it was in contact with the copper. Explain why copper in contact with iron causes the iron to rust faster than normal. …………………………………………………………………….……………………………………. ……………………………………………………………………….…………………………………. ………………………………………………………………………….………………………………. ………………………………………….………………………………….................................... [2] [Total: 9]

10 6 Ionisation is the process in which electrons are removed from atoms and cations. The