ACSBR 4NA 5105 2024 prelim Paper 4 edited

Name Class Index Number Anglo-Chinese School (Barker Road) PRELIMINARY EXAMINATION 2024 SECONDARY FOUR NORMAL (ACADEMIC) SCIENCE (CHEMISTRY) PAPER 4 5105/4 1 HOUR 15 MINUTES (FOR BOTH PAPERS) READ THESE INSTRUCTIONS FIRST Write your Name, Class and Index Number in the space provided at the top of this page and 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. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. A copy of the Periodic Table is printed on the last page. 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. At the end of the examination hand in your answers 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. For Examiner’s Use Only Paper 3 /20 Paper 4 Section A /22 Paper 4 Section B /8 TOTAL /50

Anglo-Chinese School (Barker Road) Preliminary Examination 2024 Secondary Four Normal (Academic) Science (Chemistry) 5105 Paper 4 Page 2 Section A Answer all the questions in this section. 1 One of the isotopes of bromine has the symbol shown. Br3579 (a) Complete the table to show the relative mass and relative charge of the particles found in this isotope. particle relative mass relative charge electron proton 1+ neutron 1 [2] (b) Determine the number of each of these particles in one atom of the isotope of bromine, Br3579. number of electrons = …………………………… number of neutrons = …………………………… number of protons = …………………………… [2]

Anglo-Chinese School (Barker Road) Preliminary Examination 2024 Secondary Four Normal (Academic) Science (Chemistry) 5105 Paper 4 Page 3 2 The diagram shows how the components in petroleum (crude oil) can be separated into different fractions using fractional distillation. (a) Which of the fractions, A, B, C or D has the highest boiling point? ………………………………………………………..………………………………………. [1] (b) Suggest one compound likely to be present in fraction A. ………………………………………………………..………………………………………. [1] (c) Some fractions like diesel oil, which contain larger molecules, can be broken up into smaller molecules by a chemical reaction. C16H34 → substance E + C2H4 + C3H6 (i) Name the chemical reaction. ………………………………………………………..……………………………….. [1] (ii) Deduce the chemical formula of substance E. ………………………………………………………..……………………………….. [1]

Anglo-Chinese School (Barker Road) Preliminary Examination 2024 Secondary Four Normal (Academic) Science (Chemistry) 5105 Paper 4 Page 4 (iii) Name and draw the structural formula of C3H6. name ………………………………. structural formula [2] (iv) C2H4 can act as monomers to undergo polymerisation to form polyethene. Complete the structure of polyethene. [1] (d) Bioethanol is produced from sugarcanes and is considered an alternative renewable energy source to fossil fuels like petroleum. The following description for the use of bioethanol is in a student’s notebook. Some words have been left out. Complete the description by writing in the missing words. “The use of bioethanol is often described to be environmentally sustainable or ‘carbon neutral’, as it does not ……………………………..…… the levels of carbon dioxide in our atmosphere. Bioethanol fuel is obtained through the fermentation of ……………………………..……, which is obtained during photosynthesis in sugarcane which absorbs atmospheric carbon dioxide. This volume of carbon dioxide absorbed in the production of bioethanol offsets the volume of carbon dioxide produced in the ……………………………..…… of bioethanol.” [3]

Anglo-Chinese School (Barker Road) Preliminary Examination 2024 Secondary Four Normal (Academic) Science (Chemistry) 5105 Paper 4 Page 5 3 The diagram shows two versions of the Periodic Table, where hydrogen is either placed in Group 1 or not with any group. version 1 1 2 H Li Na K version 2 1 2 13 14 15 16 17 18 H (a) With reference to version 1 of the Periodic Table, give a reason why hydrogen can be placed in the same group as the other elements in Group 1. ………………………………………………………..………………………………………. ………………………………………………………..………………………………………. [1] (b) With reference to version 2 of the Periodic Table, state one difference between the physical properties of hydrogen and the other elements in Group 1. ………………………………………………………..………………………………………. ………………………………………………………..………………………………………. [1]

Anglo-Chinese School (Barker Road) Preliminary Examination 2024 Secondary Four Normal (Academic) Science (Chemistry) 5105 Paper 4 Page 6 (c) Margarine is manufactured by passing hydrogen through polyunsaturated vegetable oils to form a solid product. (i) State the type of reaction involved in this process. ………………………………………………………..……………………………….. [1] (ii) State what is meant by the term polyunsaturated. ………………………………………………………..……………………………….. ………………………………………………………..……………………………….. [1] (d) Hydrogen was reacted with oxygen to form water. (i) Calculate the number of moles of 225 g of water. [Ar: H, 1; O, 16] Show your working. number of moles of water = …………………………. [2] (ii) Sodium from Group 1 can react with water to form sodium hydroxide and hydrogen gas. Complete the equation for this reaction. 2Na + [2]

Anglo-Chinese School (Barker Road) Preliminary Examination 2024 Secondary Four Normal (Academic) Science (Chemistry) 5105 Paper 4 Page 7 Section B Answer one question from this section. 4 Pentadecane, C15H32, can under combustion under different conditions to give different products. condition supply of oxygen products 1 excess gas P and water vapour 2 limited gas P, gas Q and gas R (a) (i) Identify gas P and state the observation when gas P is bubbled through limewater. gas P …….……………………………………………………………............. observation ..…………………………………………………………............. …………………………………………………………………………............. [2] (ii) Methane and gas P have similar effects on the environment. Describe the effect of an increased level of methane on the environment. …………………………………………………………………………............. …………………………………………………………………………............. …………………………………………………………………………............. [1] (iii) Given that gas P is an acidic gas, state the colour change when gas P is bubbled into Universal indicator solution. colour changes from ………………………… to ……..……..……………. [1]

Ang