2024_CCKSS_4E_Prelim_SciCH_P3

Marks: O LEVEL PRELIMINARY EXAMINATION 2024 65 Secondary Four Express CANDIDATE NAME CLASS INDEX NUMBER SCIENCE (CHEMISTRY) 5086/5088/03 Paper 3 22 August 2024 Candidates answer on Question Paper. 1 hour 15 minutes No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, index number and class on all the work you hand in. You may use an HB pencil for any diagrams, graphs or rough working. Write in dark blue or black pen. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. Section A Answer all questions. Write your answers in the spaces provided on the question paper. Section B Answer one question. Write your answers in the spaces provided on the question paper. A copy of the Data Sheet is printed on page 16. A copy of the Periodic Table is printed on page 17. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 17 printed pages. Setters: Mrs Trina Wong, Mdm Asmahan Vetters: Ms Ang Jia Wei, Mdm Izzati, Mr Alwin Njoo [Turn over

2024 / 4E / SCI CHEM / PRELIM / P3 2 Section A Answer all the questions in this section in the spaces provided. 1 Choose from the substances listed to answer the questions. acidified potassium manganate(VII) ammonia bromine carbon dioxide ethane ethene hydrogen methane silver chloride potassium sulfate Each substance may be used once, more than once or not at all. Identify the substance which: (a) is a gas that turns damp blue litmus paper red …………………………………….………………………………………………………. [1] (b) oxidises ethanol to ethanoic acid …………………………………….………………………………………………………. [1] (c) forms a white precipitate with barium nitrate solution …………………………………….………………………………………………………. [1] (d) is the main constituent of natural gas. …………………………………….………………………………………………………. [1] [Total: 4]

2024 / 4E / SCI CHEM / PRELIM / P3 [Turn over 3 2 (a) Magnesium reacts with sulfuric acid to produce magnesium sulfate and hydrogen gas. Fig. 2.1 shows an incomplete reaction pathway diagram for this reaction. Fig. 2.1 (i) Complete Fig. 2.1 by writing these formulae on the diagram: • Mg + H2SO4 • MgSO4 + H2 [1] (ii) Explain how Fig. 2.1 shows that the reaction is exothermic. …………………………………………………………………………………………….. ……………………………………………………………………………………… [1] (b) Magnesium is a reactive metal that can react with steam. (i) Name the products of this reaction. ……………………………………………………………………………………… [1] (ii) Table 2.1 shows some information about the reaction of four metals with steam. Table 2.1 metal reaction with steam when metal is cold beryllium reacts slowly chromium reacts slowly only when metal is very hot magnesium reacts