NYGH 2015-S3EOY-IP Chem P2

Class Register Number Name 南洋女子中学校 NANYANG GIRLS’ HIGH SCHOOL End-of-Year Examination 2015 Secondary Three CHEMISTRY 1 hour 45 minutes Paper 2 Theory Paper 0930 – 1115 hrs Wednesday 7 October 2015 Additional materials: Writing papers 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 answer 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 7, 8 and 9 Either or 9 Or. Write your answers on the separate writing paper provided. At the end of the examination, 1. fasten all your answers to Section B securely together; 2. tick 9 Either (for Either) or 9 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 one hour on Section A and no longer than 45 minutes on Section B. The use of scientific calculators is allowed. A copy of the periodic table is found on page 12. Examiner’s Use Section A Section B 7 8 9 Either 9 Or Total Setters: CHG, NHK This document consists of 12 printed pages. NANYANG GIRLS’ HIGH SCHOOL [Turn over]

2015 End-of-Year Examination Secondary Three 2 Nanyang Girls’ High School Setters: CHG, NHK Chemistry [Turn Over] Section A Answer all questions. Write your answers in the spaces provided. A1 In an experiment, two gas jars were set up as shown below. (a) State the observation when the glass disc was removed. [1] (b) What difference would you observe if the experiment is repeated using nitrogen dioxide gas instead of bromine gas? [1] (c) Pure bromine exists as a liquid and boils at 58.8oC. A small sample of liquid bromine was heated slowly and its temperature was monitored. State how one can tell whether the sample of bromine was impure. [2] Total [4] air glass disc bromine gas

2015 End-of-Year Examination Secondary Three 3 Nanyang Girls’ High School Setters: CHG, NHK Chemistry [Turn Over] A2 Brine is an impure solution of sodium chloride. The main impurity in brine is calcium chloride. It is removed by reacting brine with sodium carbonate. CaCl2 (aq) + Na2CO3(aq)  CaCO3(s) +2NaCl(aq) (a) State the type of reaction shown. [1] (b) Construct an ionic equation for the above reaction. [1] (c) Suggest how the calcium carbonate is removed from the mixture. [1] Total [3] A3 Sodium nitride (Na 3N) is a so