JPJC H2 Paper 1 Prelim Exam 2023_worked solution updated

© Jurong Pioneer Junior College [Turn Over NAME CLASS 22S JURONG PIONEER JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION 2023 CHEMISTRY 9729/01 Higher 2 Paper 1 Multiple Choice Questions 19 September 2023 1 hour Candidates answer on the Question paper. Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and exam index number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C or D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 12 printed pages.

2 © Jurong Pioneer Junior College 9729/01/J2 PRELIM EXAM/2023 Ans Key 1 B 2 C 3 C 4 B 5 D 6 D 7 C 8 A 9 A 10 D 11 D 12 A 13 C 14 A 15 C 16 C 17 D 18 A 19 A 20 D 21 D 22 B 23 C 24 D 25 D 26 B 27 B 28 C 29 A 30 B 1 Element X has eight more protons than element Y. Which statement must be correct? A Atoms of element Y are larger than atoms of element X. B Element X has at least one fully filled shell of electrons. C Element X and element Y are in the same group. D Element X and element Y are in the same period. A: X could be K whereas Y could be Na, K (X) has larger atomic radius than Na (Y). Statement A is not correct all the time. B: Element X must have at least 9 protons, which means element X must have fully filled 1s subshells. C: Y could be K whereas X could be Co, they are in the same period (Period 4) but not in the same group. Statement C is not correct all the time. D: Y could be He whereas X could be Ne, they are in the same group (Group 18) but not in the same period. Statement D is not correct all the time. Ans: B

3 © Jurong Pioneer Junior College 9729/01/J2 PRELIM EXAM/2023 [Turn Over 2 Molecular dimerisation can be described as the process in which two identical molecules combine to give a single product. Examples of dimers are: Al2Cl6 and (CH3CH2CO2H)2. Which statement about the above dimers is incorrect? A Two hydrogen bonds hold the CH3CH2CO2H molecules together in the dimer. B Each aluminium atom is surrounded by four chlorine atoms in the dimer, Al2Cl6. C CH3CH2CO2H exists as dimers when dissolved in water. D Al2Cl6 dimers are non-polar molecules. A: as seen in the diagram, there are a total of 2 hydrogen bond holding the dimer together. B: as seen in the diagram, each alumn