2019 EJC Prelims H2 Chemistry Paper 2_with solution and comments

© EJC [Turn Over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2019 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 1 8 – INDEX NUMBER CHEMISTRY Paper 2 Structured Questions 9729/02 17 September 2019 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, civics group, index number on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Paper 2 1 / 15 2 / 20 3 / 20 4 / 20 Total / 75 This document consists of 20 printed pages.

2 © EJC 9729/02/J2PE/19 For Examiner’s Use 1 The compounds of magnesium have important applications. Magnesium oxide is often used as a refractory material to line furnaces while magnesium chloride is used to de -ice roads and pavements in winter. (a) (i) Explain why magnesium oxide has the formula MgO. ................................................................................................................................ ................................................................................................................................ ............................................................................................................................ [1] (ii) State and explain the property that allows magnesium oxide to be used as a refractory material. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ............................................................................................................................ [1] (iii) Describe the action of water on magnesium oxide. Write an equation for any reaction that occurs, and suggest the pH of the solution formed. ................................................................................................................................ ................................................................................................................................ ..................................................................................................................