Zhonghua Prelim P2

ZHONGHUA SECONDARY SCHOOL PRELIMINARY EXAMINATION 2024 SECONDARY 4 EXPRESS Candidate’s Name Class Register Number CHEMISTRY 6092 /02 Paper 2 11 September 2024 1 hour 45 minutes Additional Materials: NIL READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces at the top of this page and on all separate answer paper used. Write in dark blue or black pen. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided on the question paper. Section B Answer one question. For Examiner’s Use Write your answers in the spaces provided on the question paper. Section A 70 Section B 10 Total 80 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. All essential working must be shown clearly. A copy of the Periodic Table is printed on page 24. The use of an approved scientific calculator is expected, where appropriate. This document consists of 24 printed pages.

2 Section A Answer all the questions. 1 The table below consists of four different experimental procedures. (a) Put a tick (✓) if a redox reaction had occurred. experimental procedure Put a tick (✓) if a redox reaction has occurred. (i) a copper strip added to zinc nitrate solution (ii) aqueous chlorine added to potassium iodide solution (iii) hydrogen gas passed over heated copper(II) oxide (iv) dilute sulfuric acid added to lithium hydroxide [2] (b) A student repeated (a)(ii) by replacing aqueous chlorine with aqueous bromine. Describe a difference in the rates of the two reactions and explain your answer. [2] (c) Write the chemical equation for the reaction in (a)(iii). [1] [Total: 5]

3 [Turn over 2 (a) Glasses are mainly made of silicates. Soda-lime glass is made by heating a mixture of calcium carbonate, sodium carbonate and sand in a furnace to a high temperature. The simplified structures of silicate and soda-lime glass are shown in Fig. 2.1 and Fig. 2.2. silicates soda-lime glass Fig. 2.1 Fig. 2.2 (i) Describe in terms of bonding two differences in silicate and soda-lime glass. [2] (ii) Predict and explain the electrical conductivity of soda-lime glass. [2]

4 (b) Potassium hydrox