NYGH 2018-S3EOY-IP Chem P2

Class Register Number Name NANYANG GIRLS’ HIGH SCHOOL End-of-Year Examination 2018 Secondary Three CHEMISTRY Paper 2 Theory Paper 1 hour 45 minutes Monday 8 October 2018 1000 - 1145 Additional materials: Writing paper 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 B5, B6 and B7 Either or B7 Or. Write your answers on the separate writing paper provided. At the end of the examination, 1. Fasten all your work securely together; 2. Circle B7 Either (for Either) or B7 Or (for Or) in the grid on the right to indicate the 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 60 minutes on Section A and no longer than 45 minutes on Section B. The use of approved scientific calculators is allowed. A copy of the periodic table is found on page 15. Paper 1 / 30 Paper 2 Section A / 40 B5 / 9 B6 / 11 B7 Either / B7 Or / 10 Total / 100 Setters: CJS / NHK This document consists of 15 printed pages and 1 blank page. NANYANG GIRLS’ HIGH SCHOOL [Turn over]

2018 End-of-Year Examination Secondary Three 2 Nanyang Girls’ High School Setters: CJS/ NHK Chemistry Section A (40 marks) Answer all questions. Write your answers in the spaces provided. A1 The structures of ethanoic acid and sodium ethanoate are given below. ethanoic acid sodium ethanoate (a) State the number of sigma bonds (σ bonds) and the number of pi bonds (π bonds) present in a single molecule of ethanoic acid. number of sigma bonds ……………………………………………………………… [1] number of pi bonds …………………………………………………………………… (b) Study the structure of ethanoic acid. (i) State the geometry of the bonds around the carbon atom that has been labelled with an asterisk (*). [1] …………………………………………………………………………………… (ii) Explain your answer in (bi) with reference to the number of bonding pairs and non-bonding pairs (lone pairs) of electrons in the valence shell of the carbon atom. [1] …………………………………………………………………………………… …………………………………………………………………………………… (c) Briefly explain why ethanoic acid and sodium ethanoate can both conduct electricity when dissolved in water. [1] …………………………………………………………………………………………... …………………………………………………………………………………………...

2018 End-of-Year Examination Secondary Three 3 Nanyang Girls’ High School Setters: CJS/ NHK Chemistry [Turn Over] (d) The melting point of ethanoic acid is 16.6°C, while the melting point of sodium ethanoate is 324°C. Explain why the melting