Bowen 5105 Sci Chemistry Paper 4

Class Full Name Index Number PRELIMINARY EXAMINATION 2023 I believe, therefore I am SCIENCE (CHEMISTRY) Paper 4 Secondary 4 Normal Academic Papers 3 and 4: 1 hour 15 minutes Candidates answer on the Question Paper No Additional Materials are required. 28 July 2023 READ THESE INSTRUCTIONS FIRST Write your name, class and index number on all the work you hand in. Write in dark blue or black pen on both sides of the writing paper. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in Section A and any two questions in Section B. The use of an approved scientific calculator is expected, where appropriate. In calculations, you should s how 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 12. At the end of the examination hand in your a nswers to Paper 3 and Paper 4 separately. Enter the numbers of Section B questions you have answered on the dotted line in the grid below. The numb er of marks is given in brackets [ ] at the end of each q uestion or part question. DO NOT OPEN THIS PAPER UNTIL YOU ARE TOLD TO DO SO For Examiner’s Use Section A Section B ………..... ………….. Total This document consists of 12 printed pages, including the cover page. 30 N 5105/5107/04

2 [Turn over Section A Answer all the questions in the spaces provided. A1 The diagrams below represent the particles of six different substances at room temperature and pressure. Complete the table below to show which diagrams, A to F, best represent each of the following descriptions. You may use each letter once, more than once or not at all. Substance Diagram (a) Water (b) Oxygen gas (c) Mercury (d) Mixture [4] [Total:4] For Examiner’s Use

3 [Turn over A2 In Singapore, it is an offence for the driver of a motor vehicle to leave the engine of a vehicle idlin g while it is s tationary. This measure is implemented to control the emissions generated by motor vehicles and safeguard public health. Nitrogen monoxide and carbon monoxide are the most polluting emissions from vehicle combustion engines. The concentration of each of these components depends on the mode of operation and the air-fuel ratio of the vehicle. The table below shows some information on these pollutants. scenario mode of operation air-fuel