NYGH 2020-S3EOY-IP Chem P1 and P2 Ans

Class Register Number Name 南洋女子中学校 NANYANG GIRLS' HIGH SCHOOL End-of-Year Examination 2020 Secondary Three Mark Scheme CHEMISTRY 45 minutes Paper 1 and 2 1130 - 1215 Wednesday 07 October 2020 1 hour 45 minutes Additional materials: Writing papers 0845 - 1030 READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, register number and class in the spaces at the top of this page and on any separate writing paper used. Section A (40 marks) Answer all questions. Write your answers in the spaces provided on the question paper. Section B (30 marks) Answer all questions including questions B6, B7 and B8 Either or B8 Or. Write your answers on the separate writing paper provided. At the end of the examination, 1. Fasten all your work securely together; 2. Tick B8 Either (for Either) or B8 Or (for Or) in the grid below to indicate which question you have answered; 3. Hand in Section A and Section B separately. INFORMATION FOR CANDIDATES The intended number of marks is given in the brackets [ ] at the end of each question or part question. You are advised to spend no longer than 1 hour on Section A and no longer than 45 minutes on Section B. The use of approved scientific calculators is allowed. Examiner’s Use Section A Section B B6 B7 B8 Either B8 Or Total Setters: KO/ NHK/ OWJ This document consists of 8 printed pages. NANYANG GIRLS’ HIGH SCHOOL [Turn over]

2020 End-of-Year Examination Secondary 3 IP Chemistry 2 Nanyang Girls’ High School Setters: KO/ NHK/ OWJ Chemistry/ Paper 1 & 2 Paper 1 1 C 2 D 3 B 4 A 5 C 6 D 7 C 8 A 9 C 10 C 11 B 12 C 13 C 14 D 15 A 16 C 17 A 18 B 19 C 20 A 21 C 22 A 23 D 24 B 25 C/D 26 D 27 B 28 B 29 D 30 D 1 Substance exists as liquid at 100C, so melting point is lower than 10OC; it exits as a gas at 600C, so its boiling point is lower than 600C, but higher than 100C. C 2 “homogeneous blue colouration” would mean that the particles, copper(II) ions, sulfate ions and water molecules moved around to mix in order to achieve a homogeneous state. D 3 To obtain water, we will need to carry out distillation so that water can be boiled, condensed over and collected at the distillate. B 4 Iodine undergoes sublimation. Potassium chloride is a soluble salt. Barium sulfate is an insoluble salt. Sublimation must be carried out in the first step. Followed by addition of water to dissolve potassium, then filtering to remove barium sulfate before evaporating the potassium chloride solution. A 5 Both NH3 and HCl are gases, NH3 (smaller Mr) will diffuse faster, reaching the moist red litmus paper first, and turning it blue before HCl reaches it to turn it red. C 6 Expt 1 allows the collection and measurement of gases. Expt 2 allows for the change in mass. Expt 3 allows the collection and measurement of gases. Expt 4 does not have any useful measurement of either the change in mass of reactant/product nor collection and measurement of gas. D 7 Pota