NJC_2022_H2_Chemistry_Prelim_P1_Ans

NJC/H2 Chem Preliminary Examination/01/2022 [Turn over NATIONAL JUNIOR COLLEGE SH2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Optical Answer Sheet Data Booklet 9729/01 15 September 2022 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, subject class 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 booklet. The use of an approved scientific calculator is expected, where appropriate. Instructions on how to fill in the Optical Mark Sheet Shade the index number in a 5 digit format on the optical mark sheet: 2nd digit and the last 4 digits of the Registration Number. Example: Student Examples of Registration No. Shade: 2105648 15648 This document consists of 15 printed pages and 1 blank page.

2 NJC/H2 Chem Preliminary Examination/01/2022 Suggestion solution for P1 (MCQ) 1 C 7 D 13 B 19 D 25 B 2 A 8 D 14 A 20 D 26 A 3 A 9 C 15 D 21 D 27 B 4 B 10 B 16 A 22 B 28 D 5 C 11 C 17 C 23 B 29 B 6 B 12 A 18 C 24 C 30 A

3 NJC/H2 Chem Preliminary Examination/01/2022 [Turn over 1 Technetium (Tc) is a second row transition element that does not occur naturally on Earth. One of its isotopes has 56 neutrons. What is the nucleon number of this isotope? A 43 B 56 C 99 D 112 Ans: C Refer to Periodic Table. Tc has atomic number 43, i.e. proton number = 43 nucleon number = proton + neutron = 43 + 56 = 99 2 Which row has the greater number of particles? A 1 mol of liquid sulfuric acid B 12000 cm3 of oxygen gas at s.t.p. C 32.5 g of zinc D 16 g of nitrogen gas Ans: A 1 mol of liquid sulfuric acid has 6.02  10−23 particles. There is no dissociation as the sulfuric acid is in liquid form. 12000 cm3 of oxygen gas at s.t.p has 12000 22700 = 0.5286 moles = 3.18  10−23 particles 32.5g of Zinc has 32.5 65.4 = 0.4969 moles = 2.99  10−23 particles 16 g of nitrogen gas has 16 28 = 0.5714 moles = 3.44  10−23 particles 3 Which species will have the smallest deflection when passed through the same electric field? A 23Na+ B 11B3+ C 19F− D 32S2− Ans: A Angle of deflection,   𝑐ℎ𝑎𝑟𝑔𝑒 𝑚𝑎𝑠𝑠 The species with the smallest charge to mass ratio will have the smallest deflection. 23Na+ : +1 23 11B3+ : +3 11 19F−: −1 19 32S2−: −2 32 = −1 16

4 NJC/H2 C