2020 EJC JC2 Prelim H2 Chemistry Paper 3 Suggested Solutions

© EJC [Turn Over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2020 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 1 9 – INDEX NUMBER CHEMISTRY Paper 3 Free Response 9729/03 17 September 2020 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. If addition space is required, you should use the pages at the end of this booklet. The question number must be clearly shown. Section A Answer all the questions Section B Answer one question. 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 3 1 / 22 2 / 19 3 / 19 4 / 20 5 / 20 Total / 80 This document consists of 32 printed pages.

2 © EJC 9729/03/J2PE/20 Section A Answer all the questions in this section. 1 (a) Describe and explain the trend observed in the thermal stabilities of the carbonates of Group 2 elements. [3] (b) (i) Elements in period 3 can react with chlorine gas to form different chlorides. State the types of bonding in the chlorides of sodium, aluminium and silicon. [1] (ii) Write appropriate equations to illustrate the reaction s, if any, when separate samples of sodium chloride, aluminium chloride and silicon chloride were added to excess water. [3] ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ................................ ................................ ............................. ................................ ....................