AMKSS Prelim P4 2025

1 AMKSS 4NA Prelim Exam 5105/04/2025 [Turn Over Name Form Class Index Number ANG MO KIO SECONDARY SCHOOL PRELIMINARY EXAMINATION 2025 SECONDARY FOUR NORMAL ACADEMIC SCIENCE 5105/04 Paper 4 Chemistry 5 August 2025 Setter: Ms Audrey Ferng Paper 3 and 4: 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and index number in the spaces at the top of this paper. Write in dark blue or black pen. You may use a 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. Section B Answer one question. Write your answers in the spaces provided. The use of an approved scientific calculator is expected, where appropriate. In calculations, you should show all the steps in your working, giving your answer at each stage. You are advised to spend no longer than 30 minutes on Paper 3. You may proceed to answer Paper 4 as soon as you have completed Paper 3. A copy of the Periodic Table is printed on page 11. At the end of the examination hand in your answer to Paper 3 and Paper 4 separately. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 11 printed pages and 1 blank page.

2 AMKSS 4NA Prelim Exam 5105/04/2024 Section A Answer all the questions in the spaces provided. 1 (a) Complete the table on the oxygen-17 and oxygen-18 atoms. atom nucleon number number of protons number of neutrons number of electrons oxygen-17 8 oxygen-18 8 [2] (b) Oxygen reacts with non-metals such as carbon and sulfur to form non-metal oxides. Coal contains carbon and traces of sulfur. When coal undergoes combustion, carbon dioxide and sulfur dioxide are formed. (i) Sulfur dioxide is an air pollutant which is harmful to the environment State one source of sulfur dioxide and describe one of its effects on the environment. source: ………………………………………………………………….…………………………… ………………………………………………………………………………………………………… effect: .……………………………………………………………………………………………….. ………………………………………………………………………………………………………… [2] (ii) Describe a test to identify carbon dioxide gas. test: ……………………………………………………………………………………………….…. observation: …………………………………………………………………………………………. [2] (iii) Draw a ‘dot and cross’ diagram of a carbon dioxide molecule, showing only the outer shell electrons. [2] [Total: 8]

3 AMKSS 4NA Prelim Exam 5105/04/2025 [Turn Over 2 Chlorine, bromine and iodine are elements found in Group 17 of the Periodic Table and they exist as diatomic molecules. (a) Explain why these elements have similar chemical properties. ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… [1] (b) Describe a change in physical property down Group 17. ………………………………………………………………………………………………………… [1] (c) A secret letter was written with ink made from potassium iodide solution. When the secret letter was placed in a bottle containing chlorine gas, some brown writing appeared. Explain why the brown writing appeared. ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… [2] (d) Bromine has a melting point of -7.2 ⁰C and a boiling point of 58.8 ⁰C. Describe the arrangement and movement of the molecules in bromine at 35 ⁰C. arrangement: ……………………………………………………………………………………… movement: …………………………………………………………………………………………. [2] [Total:6]

4 AMKSS 4NA Prelim Exam 5105/04/2024 3 (a) Hydrogen gas is used to produce margarine from vegetable oil as shown in the diagram. (i) Vegetable oil is unsaturated. With reference to the diagram, which part of the structure of vegetable oil shows that it is unsaturated? ……………………………………………………………………………………………………….. [1] (ii) State the observation when margarine and vegetable oil are respectively added to aqueous bromine. observation with margarine: ………………………………………………………………………. ………………………………………………………………………………………………………… observation with vegetable oil: …………………………………………………………………… ………………………………………………………………………………………………………… [2] H2 hydrogen part of a vegetable oil molecule part of a margarine molecule nickel powder

5 AMKSS 4NA Prelim Exam 5105/04/2025 [Turn Over (b) Ethene gas can be prepared in the laboratory as shown in the diagram. (i) Ethene reacts with chlorine to form a gaseous product. Complete the chemical equation and draw the full structural formula of the product. C2H4 + Cl2 →…………………………….. full structural formula of product: [2] (ii) Hexene, C6H12, is another hydrocarbon in the same homologous series as ethene. Calculate the mass of 15 mol of C6H12. [Relative atomic masses: Ar: H,1; C, 12] mass = ……………………………. [2] (iii) Name the polymer formed when hexene undergoes addition polymerisation. ……………………………………………………………………………………………………….. [1] [Total: 8] mineral wool soaked in paraffin ethene gas safety valve pieces of porous pot (porcelain) heat

6 AMKSS 4NA Prelim Exam 5105/04/2024 Section B Answer any one question from this section. 4 (a) The diagram shows the apparatus set-up to study the rusting of iron. The apparatus was left for one week. (i) Explain why the water level in the test-tube had risen after one week. …………………………………………………………………………………………………….. [1] (ii) State one method of rust prevention. …………………………………………………………………………………………………….. [1] (iii) Iron reacts with sulfuric acid to form a gas and iron(II) sulfate. Write a balanced chemical equation for the reaction. …………………………………………………………………………………………………….. [1] test-tube Iron filings on damp cotton wool air test-tube iron filings on damp cotton wool 2nd level of water 1st level of water air

7 AMKSS 4NA Prelim Exam 5105/04/2025 [Turn Over (b) The diagram shows some experiments carried out by a student investigating the reactions of three metals, Q, R and S with dilute hydrochloric acid and water. With reference to the diagram, rank metals Q, R and S in order of reactivity. most reactive ………………………… ………………………… least reactive ………………………… [1] (c) (i) A metal oxide is formed when a metal reacts with oxygen. Draw the ‘dot and cross’ diagram of magnesium oxide. Show only outer shell electrons. [2] (ii) Explain in terms of structure and bonding why magnesium oxide has a high melting point. …………………………………………………………………………………………………….. …………………………………………………………………………………………………….. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. [2] [Total: 8] metal Q metal S metal Q metal R no reaction water dilute hydrochloric acid no reaction burning splint

8 AMKSS 4NA Prelim Exam 5105/04/2024 5 A student conducted a set of experiment to investigate the temperature change when different masses of zinc metal are added separately to 50.0 cm3 samples of copper(II) sulfate solution. The student followed the follow