YIJC 2023 H2 Chem Prelim P1 Worked Solutions (1)

©YIJC [Turn over YISHUN INNOVA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME TEACHER’S COPY CG INDEX NO CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet 9729/01 15 September 2023 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid/tape. Write your name and class 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 and 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 16 printed pages.

©YIJC [Turn over 2 1 A medal has a total surface area of 150 cm2. It is evenly coated with silver by electrolysis. Its mass increases by 0.216 g. How many atoms of silver are deposited per cm2 on the surface of the medal? A 8.0 x 1018 B 1.8 x 1019 C 8.7 x 1020 D 1.2 x 1021 Answer: A Amount of Ag = 0.216 / 107.9 = 2.00185 x 10-3 mol Number of Ag = 2.00185 x 10-3 x 6.02 x 1023 = 1.20511 x 1021 Number of atom per cm2 = 1.20511 x 1021 / 150 = 8.03 x 1018 2 Which gas would behave most like an ideal gas under room conditions? A ammonia B helium C krypton D nitrogen Answer: B Ideal gas should have negligible intermolecular forces of attraction. Ammonia has hydrogen bonding which has the strongest IMF. Between helium, krypton and nitrogen, helium has the smallest electron cloud size so weakest id-id.

©YIJC [Turn over 3 3 In two separate experiments a beam of protons and a beam of He2+ 2 4 particles, travelling at the same velocity, pass through an electric field as shown. Which statements are correct? 1 Both beams are deflected in the same direction. 2 The proton beam travels in a straight path towards the negatively charged plate. 3 The protons are deflected to a larger extent than the He2+ 2 4 particles. A 1 and 2 B 1 and 3 C 2 and 3 D 1 only Answer: B Statement 1 is correct. Both protons and He2+ 2 4 particles are positively charged, they will be deflected in the same direction, towards the negatively charged plate. Statement 2 is incorrect. The proton beam travels in an angle similar to a circular path after