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 rapidly silver no reaction Arrange the four metals in order of their reactivity, starting with the least reactive metal first. ……………………………………………………………………………………… [1] [Total: 4] energy / kJ progress of reaction

2024 / 4E / SCI CHEM / PRELIM / P3 4 3 Atoms of non-metallic elements can combine with other atoms to form many different compounds. (a) One of such compounds, ammonia is a non-conductor of electricity and has a low melting point. (i) Name the type of bonding present in ammonia. ……………………………………………………………………………………… [1] (ii) Draw a ‘dot and cross’ diagram to show the arrangement of electrons in a molecule of ammonia in the space given. Show only the outer shell electrons. [Proton numbers: H, 1; N, 7] [2] (b) Another compound, magnesium chloride, has a high melting point and is a conductor of electricity when molten. Explain the following statements: (i) Magnesium chloride has a high melting point. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. ……………………………………………………………………………………… [2] (ii) Magnesium chloride is a conductor of electricity when molten. …………………………………………………………………………………………….. ……………………………………………………………………………………… [1] [Total: 6]

2024 / 4E / SCI CHEM / PRELIM / P3 [Turn over 5 4 In recent years there are great concerns in the rise of carbon dioxide and air pollutants, such as nitrogen monoxide and carbon monoxide, in the atmosphere. (a) State the percentage by volume of nitrogen in clean dry air. ………………. % [1] (b) Describe how nitrogen monoxide is formed in a car engine. …………………………………………………………………………………………………… …………………………………….………………………………………………………. [1] (c) Carbon monoxide is also formed in a car engine. State one effect of carbon monoxide in the air on health. …………………………………………………………………………………………………… …………………………………….………………………………………………………. [1] (d) The percentage by volume of carbon dioxide in the atmosphere is regulated by the carbon cycle. Describe how the percentage by volume of carbon dioxide is regulated by the carbon cycle. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………….………………………………………………………. [3] [Total: 6]

2024 / 4E / SCI CHEM / PRELIM / P3 6 5 Table 5.1 lists the number of protons, neutrons and electrons in several different particles. Table 5.1 particle number of protons number of neutrons number of electrons C 1 0 1 D 3 3 2 E 7 7 7 F 8 9 8 G 8 10 8 H 9 10 10 Which of the particles, C, D, E, F, G and H in Table 5.1, fit each of the following descriptions? Each letter may be used once, more than once or not at all. (a) an atom with a mass number of 18 ………… [1] (b) an atom with 5 electrons in its outer shell ………… [1] (c) an ion of a metal ………… [1] (d) are isotopes of the same element ………… and ………… [1] (e) a negatively charged ion ………… [1] [Total: 5] 6 A student has a mixture of solid ionic compounds. The student adds the mixture to a beaker with water and stirs the contents of the beaker. The beaker contains a colourless solution and an insoluble black solid. (a) Draw a diagram to show how the student separates the colourless solution and the black solid. Label the black solid and the colourless solution in your diagram. [2]

2024 / 4E / SCI CHEM / PRELIM / P3 [Turn over 7 (b) Fig. 6.1 and Fig. 6.2 describe some of the tests carried out on the colourless solution and the black solid respectively. Fig. 6.1 Fig. 6.2 Suggest the identity of substances M, N, O, P and Q. M ……………………………….…………….... N ……………………………….…………….... O ……………………………….…………….... P ……………………………….…………….... Q ……………………………….…………….... [5] (c) Write a balanced chemical equation, including state symbols, for any one of the reactions shown in Fig. 6.1 or Fig. 6.2. …………………………………..………..……………………………….…………….... [3] [Total: 10] colourless solution add dilute nitric acid and aqueous barium nitrate colourless gas M that forms white precipitate with limewater white precipitate N add aqueous sodium hydroxide black solid warm with dilute hydrochloric acid blue solution O light blue precipitate P white precipitate Q add dilute nitric acid and aqueous silver nitrate

2024 / 4E / SCI CHEM / PRELIM / P3 8 7 Table 7.1 shows some information about the homologous series of carboxylic acids. Table 7.1 name structure boiling point / oC methanoic acid HCOOH 101 ethanoic acid CH3COOH 118 propanoic acid CH3CH2COOH 141 but