Zhonghua Prelim P1

1 [Turn over ZHONGHUA SECONDARY SCHOOL PRELIMINARY EXAMINATION 2024 SECONDARY 4 EXPRESS Candidate’s Name Class Register Number CHEMISTRY 6092 /01 Paper 1 21 August 2024 1 hour Additional Materials: OTAS READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, index number and class on the OTAS in the spaces provided. There are forty questions on this paper. Answer all questions. For each question, there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate OTAS. Read the instructions on the OTAS very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. A copy of the Periodic Table is printed on page 20. The use of an approved scientific calculator is expected, where appropriate. This document consists of 19 printed pages and 1 blank page.

2 1 The following set-up was used to obtain a sample of carbon monoxide in the laboratory. The sample of carbon monoxide collected is found to be an impure mixture of two gases. How can a pure sample of carbon monoxide be obtained? A bubble the stream of gas from X into a flask containing aqueous sodium hydroxide before collection B bubble the stream of gas from X into a flask containing concentrated sulfuric acid before collection C use concentrated sulfuric acid instead of dilute hydrochloric acid for the reaction with calcium carbonate D use larger pieces of charcoal 2 Three separations are listed. 1 obtaining ethanol from a mixture of water and ethanol 2 obtaining water from a mixture of oil and water 3 obtaining water from calcium chloride solution Which techniques would be involved in these separations? 1 2 3 A evaporation simple distillation simple distillation B fractional distillation use of a separation funnel evaporation C fractional distillation use of a separation funnel simple distillation D simple distillation filtration fractional distillation dilute hydrochloric acid charcoal X carbon monoxide heat calcium carbonate gas jar water

3 [Turn over 3 The apparatus below is set up, using different gases in the two inverted beakers. Which pair of gases would cause an upward movement of the water level at U? gas 1 gas 2 A helium carbon dioxide B nitrogen carbon monoxide C nitrogen hydrogen D oxygen hydrogen 4 A gaseous mixture is made up of argon, chlorine and nitrogen. Which diagram shows a pure sample of this mixture? A B C D

4 5 The formulae of four covalent molecules are shown. 1 CH3CH2OH 2 CH3COOH 3 H 2O 4 O 2 In which pair of molecules does oxygen form at least one double bond in both molecules?