2022 HCI Prelim P2 Question Paper

This document consists of 17 printed pages and 2 blank pages. HWA CHONG INSTITUTION C2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 21S CENTRE NUMBER INDEX NUMBER CHEMISTRY Paper 2 Structured Questions Candidates answer on the Question Paper Additional Materials: Data Booklet 9729/02 29 August 2022 2 hours READ THESE INSTRUCTIONS FIRST Write your name, CT group, centre number and index number clearly in the spaces above. 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. Answer all questions in the spaces provided in the Question Paper. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 / 11 2 / 9 3 / 13 4 / 15 5 / 27 Deductions Total / 75

2 © Hwa Chong Institution 2022 9729/02/C2 Preliminary Exam [Turn over Answer all the questions in the spaces provided. DO NOT WRITE IN THIS MARGIN 1 Fossil fuels which are found in deposits have been formed from plants and animals that lived millions of years ago. When fossil fuels are burned in internal combustion engines, CO 2 and H 2O are the main products, with NO and SO2 also being formed. (a) (i) What class of compound, present in fossil fuels, produces CO 2 and H 2O on combustion? ……………………………………………………………………………………………….[1] (ii) NO and NO 2, collectively known as oxides of nitrogen, are pollutants that are also formed during combustion in motor vehicles. Write equations to show how each of these two gases are formed in vehicle engines. …………………………………………………………………………………………………. ………………………………………………………………………………………..……..[1] (iii) State one harmful effect of oxides of nitrogen on the environment. ……………………………………………………………………………………………….[1] To meet emission standards in Singapore, sulfur emissions from cars have to be lower than 50 parts per million (ppm). This means that there should be less than 50 molecules of SO 2 for every 1 × 106 molecules of gas in the fuel exhaust for it to meet regulations. (b) (i) A sample of fuel was combusted at 900 C and 10.0 bar. At the end of the reaction, 63.2 dm3 of gas was collected under the same conditions. Determine the amount of gas, in moles, produced by combustion of the fuel sample. [2] (ii) Given that 0.0183 g of SO2 was produced in (b)(i), calculate the concentration of SO2, in parts per million, and explain whether the fuel exhaust meets the sulfur emission standards. [2]

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