SAJC 2022 P1 ANS

1 [TURN OVER ST ANDREW’S JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATIONS HIGHER 2 CANDIDATE NAME STUDENT WORKED SOLUTIONS CLASS 2 1 S CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice 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, glue or correction fluid. Write your name and class on the Answer Sheet in the spaces provided. 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. 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 19 printed pages (including this cover page) and 1 blank page.

2 [TURN OVER 1 2 3 4 5 6 7 8 9 10 C D C A B A A C B C 11 12 13 14 15 16 17 18 19 20 C B D C C D D A D C 21 22 23 24 25 26 27 28 29 30 C B D B A B B C B D 1 Use of the Data Booklet is relevant to this question. Which statements about chromium and its compounds are correct? 1 The valence electronic configuration of Cr contains both an unpaired s electron and an unpaired p electron. 2 One of the 3d orbitals in chromium atom has only 2 lobes. 3 There are 58 electrons and 60 neutrons in the 52Cr16O42− ion. A 1, 2, and 3 B 1 and 2 C 2 and 3 D 1 only 1. The electronic configuration of Cr is [Ar]3d54s1. Cr contains both an unpaired s electron and an unpaired d electron (not p electron). 2. Only the 3dz2 d orbital has 2 lobes. 3. No of electrons = 24 + (4 x 8) + 2 = 58 No of neutrons = (52 – 24) + 4(16 – 8) = 60 Answer: C

3 [TURN OVER 2 The following graph shows the second ionisation energy of eight consecutive elements in Period 2 and 3. Which of the options A, B, C or D is silicon? B must be group 1 as the second electron is removed from the inner shell hence resulting in a large energy gap. Hence, D is group 14 and belongs to silicon. Answer: D 3 Which option is correct? Molecule Planar Polarity A Xenon difluoride Yes Polar B Chlorine(I) oxide No Non-polar C Methanal Yes Polar D Dichloromethane No Non-polar Molecule Planar Polarity Diagram  A Xenon difluoride Linear (Yes) Non-polar  B Chlorine(I) oxide Bent (Yes) Polar ✓ C Methanal Trigonal Planar (Yes) Polar 2nd IE Atomic number A B C D

4 [TURN OVER  D Dichloromethane Tetrahedral (No) polar Answer: C 4 Which statements about ethanoic acid are correct? 1 1 molecule of ethanoic acid has 4 lone pairs of electrons. 2 Gaseous ethanoic acid forms a dimer comprising of two hydrogen bonds within a ring of 8 atoms. 3 The CꟷC bond