2019 TMJC H2 Chem Prelim P2 QP

Tampines Meridian Junior College 2019 JC2 Prelim H2 Chemistry CANDIDATE NAME CIVICS GROUP __________________________________________________________________________________ H2 CHEMISTRY 9729/02 Paper 2 Structured Questions 19 September 2019 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name and civics group in the spaces at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. __________________________________________________________________________________ This document consists of 19 printed pages. Examiner’s Use Paper 1 MCQ / 30 Paper 2 Q1 / 14 Q2 / 9 Q3 / 13 Q4 / 12 Q5 / 11 Q6 / 16 / 75 Paper 3 / 80 Paper 4 / 55 Total / 100 Grade TAMPINES MERIDIAN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION

2 Tampines Meridian Junior College 2019 JC2 Prelim H2 Chemistry 1 (a) Carbon forms compo unds with Group 16 elements such as oxygen, sulfur and selenium. The properties of some of these compounds are given below. compound structure net dipole moment boiling point / C CO2 O=C=O 0 sublimes CS2 S=C=S 0 46 COS S=C=O 0.71 –50 COSe Se=C=O 0.73 –22 (i) Explain, in terms of structure and bonding, the difference in the boiling points of CS2 and COS. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………….[2] (ii) Explain why  CO2 has no net dipole moment.  COSe has a greater net dipole moment than COS. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. ……………………………………………………………………………………….[2]

3 Tampines Meridian Junior College 2019 JC2 Prelim H2 Chemistry Carbon forms the backbone of organic compounds. Hydrocarbons are the simplest organic compounds that contain carbon and hydrogen. (b) Compound A is an isomer of the hydrocarbon octane, C8H18. A Controlled chlorination of compound A in the presence of UV light produces different mono-chlorinated products with a molecular formula of C8H17Cl. (i) Suggest the total number of constitutional isomers which can be formed from the possible mono-chlorination of compound A. Draw the structural formulae of any two of these products. Total number of possible mono-chlorinated products = ……………………… [3] (ii)