2023 EJC H2 Chemistry Prelims Paper 1 Worked Solutions

© EJC [Turn Over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2023 General Certificate of Education Advanced Level Higher 2 CHEMISTRY Paper 1 Multiple Choice 9729/01 21 September 2023 1 hour 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, civics group and registration 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 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 question paper. The use of an approved scientific calculator is expected, where appropriate. This document consists of 12 printed pages.

2 © EJC 9729/01/J2PE/23 1 D 11 C 21 C 2 C 12 D 22 C 3 A 13 B 23 A 4 B 14 A 24 D 5 B 15 B 25 D 6 D 16 B 26 D 7 C 17 B 27 A 8 A 18 B 28 A 9 A 19 D 29 D 1 A beam of particles contains D‒ and 4He2+. All particles approach an electric field at the same speed. (D is deuterium, 2H) Which row describes the behaviour of the species? D‒ 4He2+ relative extent of deflection A deflect towards (‒) plate deflect towards (+) plate 4He2+ deflected more than D‒ B deflect towards (‒) plate deflect towards (+) plate 4He2+ deflected less than D‒ C deflect towards (+) plate deflect towards (‒) plate 4He2+ deflected more than D‒ D deflect towards (+) plate deflect towards (‒) plate 4He2+ deflected to the same extent as D‒ Answer: D Angle of deflection  𝑐ℎ𝑎𝑟𝑔𝑒 𝑚𝑎𝑠𝑠 Angle of deflection of D‒  −1 2 Angle of deflection of He2+  +2 4 Thus, He2+ and D‒ are deflected to the same extent, but directed towards plate of opposite charge. beam of particles + ‒

3 © EJC 9729/01/J2PE/23 [Turn over 2 The melting point of calcium, 839 ºC, is much higher than the melting point of sodium, 98 ºC. Which statement is most relevant in explaining this difference? A The calcium atom is larger than the sodium atom. B The calcium atom is heavier than the sodium atom. C The calcium ion, Ca2+, has a higher charge than the sodium ion, Na+. D The calcium ion, Ca2+, contains more electrons than the sodium ion, Na+. Answer: C Calcium and sodium are metals. Their melting points depend on the strength of their metallic bonds. Strength of metallic bonds depend on: • charge of metal ion • size of metal ion • no. of valence electrons which can be delocalised (more delocalised electrons ⇒ greater attraction between metal cations and delocalised electrons) 3 For a fixed mass of an ideal gas, whi