NYGH 2016-S3EOY-IP Chem P2

Class Register Number Name NANYANG GIRLS’ HIGH SCHOOL End-of-Year Examination 2016 Secondary Three CHEMISTRY 1 hour 45 minutes Paper 2 Theory Paper 1015 – 1200 hrs Wednesday 5 October 2016 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 13. Examiner’s Use Section A Section B 7 8 9 Either 9 Or Total Setters: SCheong, LSM This document consists of 13 printed pages and 1 blank page. NANYANG GIRLS’ HIGH SCHOOL [Turn over]

2016 End-of-Year Examination Secondary Three 2 Nanyang Girls’ High School Setters: SCheong, LSM Chemistry [Turn Over] A1 Mosquitoes are attracted to humans due to the chemicals we release. Two main chemicals they respond to are carbon dioxide and ammonia. Using the following transparent setup, James carried out an experiment to find out if mosquitoes are more attracted to carbon dioxide or ammonia. Through chemical reactions, carbon dioxide was produced in A and ammonia in B. When the reactions are completed, he removed all removable covers simultaneously to release the gases and mosquitoes. He monitored the direction of mosquito travel. More mosquitoes flew to B than to A, leading James to conclude that mosquitoes are more attracted to ammonia. (a) Write the chemical formula of a substance that James could add to hydrochloric acid in A to produce carbon dioxide and to potassium hydroxide in B to produce ammonia gas. [2] A: B: Section A Answer all questions. Write your answers in the spaces provided. Legend  direction of mosquito travel removable cover

2016 End-of-Year Examination Secondary Three 3 Nanyang Girls’ High School Setters: SCheong, LSM Chemistry [Turn Over] (b) How would James know that the reaction in A had completed? Suggest an observation. [1] (c) James’ teacher