2021 SNGS Prelim P2

This document consists of 20 printed pages. [Turn over Name: _______________________________ ( ) Class:___________ PRELIMINARY EXAMINATION GENERAL CERTIFICATION OF EDUCATION ORDINARY LEVEL _____________________________________________________________________ CHEMISTRY 6092/02 Paper 2 23 August 2021 1hour 45minutes _____________________________________________________________________ READ THESE INSTRUCTIONS FIRST Write your name, register number, and class clearly in the spaces provided at the top of this page. Write in dark blue or black pen only. You may use a soft pencil for any diagrams or graphs. Do not use highlighters, glue, and correction fluid or correction tape. Section A Answer all questions in the spaces provided. Section B Answer all three questions, the last question is in the form of either/or. Answer all questions in the spaces provided. A copy of Periodic Table is provided on page 2. The number of marks is given in brackets [ ] at the end of each question or part question. The use of a scientific calculator is expected, where appropriate. For Examiner’s Use Section A (50) Section B (30) Total (80)

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3 Section A Answer all the questions in this section in the space provided. The total mark for this section is 50. A1 The following table shows some substances and their properties. substance melting point (oC) boiling point (oC) solubility in water electrical conductivity when solid when liquid A 3550 4830 insoluble poor poor B -114 -85 soluble poor poor C 1538 2862 insoluble good good D 801 1413 soluble poor good E 98 882 soluble good good (a) Explain why (i) B has a low melting point while A has a very high me lting point , in terms of bonding. ……………………………………………………………….....……………… ……………………………………………………………….....……………… ………………………………………………………………………………… …..……………………………………………………………………………… ………………………………………………………………………………..[3] (ii) E, but not D, can conduct electricity at room temperature, in terms of bonding and structure. ……………………………………………………………….....……………… ……………………………………………………………….....……………… ………………………………………………………………………………… …..……………………………………………………………………………… ………………………………………………………………………………..[3] (b) Given that E is an element, suggest a possible identity for E. ………………………………………………………………………………...........[1]

4 (c) C is an element used as a catalyst in the Haber process. State the identity of C. ……………………………………………………………………..........................[1]