2022 HCI H2 Chemistry Promo P3 QP

This document consists of 16 printed pages. HWA CHONG INSTITUTION C1 Promotional Examination Higher 2 CANDIDATE NAME CT GROUP 22S CHEMISTRY Paper 3 Free Response Candidates answer on the Question Paper. Additional Materials: Data Booklet 9729/03 28 September 2022 55 min READ THESE INSTRUCTIONS FIRST Write your name and CT group 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. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. If additional space is required, you should use the pages at the end of this booklet. The question number and part must be clearly shown. Section A Question 1 is a compulsory question. Section B Answer only one question from this section. A Data Booklet is provided. The use of an approved scientific calculator is expected, where appropriate. You are reminded of the need for good English and clear presentation in your answers. At the end of the examination, fasten all your work securely together. The number of ma rks is given in brackets [ ] at the end of each question or part question. FOR EXAMINER’S USE Question No. Marks obtained 1 / 20 ^Circle the question attempted below. ^ 2 / 3 / 15 Deductions (s.f.) Deductions (units) Total Marks 35 No. of sheets of writing paper submitted (write 0 if none)

2 © Hwa Chong Institution 2022 9729/03/C1 Promotional Exam 2022 [Turn over Section A Question 1 is a compulsory question. All candidates should answer this question. DO NOT WRITE IN THIS MARGIN 1 (a) Volcanology is the scientific study of volcanoes. At the Earth’s core, there is a molten mixture of rock, gases and crystals called magma. During a volcanic eruption, magma makes its way to the surface and flows out as lava. The most abundant elements in magma are oxygen and silicon. (i) State the electronic configuration of an atom of silicon. [1] (ii) Describe one similarity and one difference between a 3s orbital and a 3p orbital. [2] (iii) Describe one difference between a 2p orbital and a 3p orbital. [1] …………………………………………………………...………………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… …………………………………………………………...………………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… …………………………………………………………...………………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… …………………………………………………………...………………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………..…………………………………… ……………………………………………………….………………………..…………………… ……………………………………………………….…………………………..…………………

3 © Hwa Chong Institution 2022 9729/03/C1 Promotional Exam 2022 [Turn over (b) Silica, SiO2, is a major component of lava. At the high temperatures during eruptions, silica in the lava can react with other metals present to form a variety of salts, such as basalt. Analysis of a sample of basalt produced the following composition: element mass percentage (%) Ca 18.51 Mg 11.22 Si 25.95 O 44.32 DO NOT WRITE IN THIS MARGIN (i) Use the information provided above to determine the empirical formula of basalt. [2] (ii) Basalt can be thought of as a mixture of a salt of calcium and a salt of magnesium, both containing the same anion. Based on your answer to (b)(i), state the formula of this anion. [1] ……………………………………..…………………….………………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….…………………………………………..… ……………………………………………………….…………………………………………..… ……………………………………………………….…………………………………………..… ……………………………………..…………………….………………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….…………………………………………..… ……………………………………………………….…………………………………………..… ……………………………………………………….…………………………………………..… ……………………………………..…………………….………………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….…………………………………………..… ……………………………………………………….…………………………………………..… ……………………………………..…………………….………………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….…………………………………………..… ……………………………………………………….…………………………………………..… ……………………………………………………….…………………………………………..…

4 © Hwa Chong Institution 2022 9729/03/C1 Promotional Exam 2022 [Turn over (c) Hydrocarbon reservoirs can often be found in volcanic zones. Pentenes, one of the byproducts of thermal cracking of hydrocarbons, are alkenes with the formula C5H10. Pentenes are generally very volatile and boil just above room temperature. DO NOT WRITE IN THIS MARGIN (i) D, E, and F are three straight-chain pentenes with different structures. E and F are a pair of stereoisomers. Draw the structures of D, E and F, and name each of them. [3] (ii) Explain how the isomerism between E and F arises. [2] Hydrogenation is a useful way to convert unsaturated hydrocarbons, such as pentenes, into saturated hydrocarbons. C5H10(g) + H2(g) → C5H12(g) This conversion is usually conducted in the presence of a finely divided metal catalyst. Without the catalyst, pentenes do not react readily with hydrogen gas. (iii) Explain, with the aid of a labelled Maxwell-Boltzmann distribution diagram, the effect on a rate constant of adding a catalyst. [3] (iv) At very low pressures, the reaction rate is directly proportional to the partial pressure of each reactant, while at higher pressures, the reaction rate appears to be independent of the partial pressure of each reactant. Suggest an explanation for this observation. [2] ………………………………………………..………….………………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..………………………………………

5 © Hwa Chong Institution 2022 9729/03/C1 Promotional Exam 2022 [Turn over ………………………………………………..………….………………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ………………………………………………..………….………………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ……………………………………………………….……..……………………………………… ………………………………………………..………….………………………………………… ………