SRJC H2 Chem 2012 Prelim P1 QP

1 SERANGOON JUNIOR COLLEGE General Certificate of Education Advanced Level Higher 2 Candidate Name Class CHEMISTRY 9647/01 Preliminary Examination 24 August 2012 Paper 1 Multiple Choice 1 hour Additional Materials: Data Booklet Optical Mark Sheet (OMS) READ THESE INSTRUCTIONS FIRST On the separate multiple choice OMS given, write your name, FIN/NRIC and class in the spaces provided. Shade correctly your class and FIN/NRIC number. Eg. If your NRIC is S9306660Z, shade S9306660Z for the item “index number”. There are forty questions in 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 using a soft pencil on the separate OMS. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. You are advised to fill in the OMS as you go along; no additional time will be given for the transfer of answers once the examination has ended. Any rough working should be done in this question paper. This document consists of 19 printed pages and 1 blank page SRJC PRELIM 9647 P1 Turn Over]

2 SRJC PRELIM 9647 P1 Turn Over] Section A For each question there are four possible answers, A , B, C and D. Choose the one you consider to be correct. 1 To determine the percentage of nitrogen present in a snack, 1.0 g of the snack was boiled with concentrated sulphuric acid to convert all the nitrogen into ammonium sulphate. The ammonium salt obtained was then boiled with excess aqueous sodium hydroxide to liberate the ammonia, which was passed into 25.0 cm 3 of 0.20 mol dm –3 hydrochloric acid. The unreacted hydrochloric acid required 20.0 cm 3 of 0.10 mol dm –3 aqueous sodium hydroxide for complete neutralisation. What is the percentage by mass of nitrogen in the snack? A 2.8% B 4.2% C 7.2% D 8.4% 2 In an experiment, 25 .0 cm3 of 0.2 0 mol dm –3 solution of K 2AO4 reacted exactly with 25.0 cm 3 of 0.10 mol dm –3 a queous sodium sulfate(IV). The half- equation for the oxidation of the sulfate(IV) ion is shown below. SO32– (aq) + H2O (l) ® SO42– (aq) + 2H+ (aq) + 2e– Calculate the final oxidation state of A. A +2 B +3 C +4 D +5 3 Two elements D and E have the following properties. · D and E form ionic compounds Na2D and Na2E respectively. · Element E forms EF6 molecules whereas D is not able to do so. Which pair of electronic configurations for D and E is correct? D E A [He] 2s2 2p2 [Ne] 3s2 3p4 B [He] 2s2 2p2 [Ne] 3s2 3p2 C [He] 2s2 2p4 [Ne] 3s2 3p2 D [He] 2s2 2p4 [Ne] 3s2 3p4

3 SRJC PRELIM 9647 P1 Turn Over] 4 The diagram below shows liquid trichloromethane and liquid benzene flowing from burettes 1 and 2 respectively. What would happen to the flow of the liquids trichloromethane and benzene when a negatively-charged rod is brought near to each of them? Liquid trichloromethane Liquid benz