ACJC Prelim P1(Worked_Solution)

1 © ACJC 2018 9729/01/Prelim/2018 [Turn over ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examination C H E M I S T R Y 9729/01 Higher 2 Paper 1 Multiple Choice 29 August 2018 1 hour Additional Materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluids. Write your name, index number and tutorial class on t he Answer Sheet in the spaces provided unless this has been done for you. There are thirty 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 Answer Sheet. Read the instructions on the Answer Sheet 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. The use of an approved scientific calculator is expected, where appropriate. This document consists of 18 printed pages. 9729/01/Prelim/18 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2018 Department of Chemistry [Turn over

2 © ACJC 2018 9729/01/Prelim/2018 [Turn over 1 D 11 C 21 D 2 B 12 B 22 C 3 B 13 D 23 B 4 A 14 D 24 A 5 B 15 D 25 A 6 C 16 B 26 D 7 C 17 A 27 A 8 C 18 D 28 B 9 A 19 A 29 C 10 B 20 D 30 B 1 The Basic Oxygen steel-making process is a method of preparing steel from carbon-rich molten pig iron. The process is basic because chemical bases are added to remove impurities. One such impurity is phosphorus pentoxide, P 4O10. Calcium oxide, CaO, is added to remove it and the only product of the reaction is the salt, calcium phosphate, Ca3(PO4)2. How many moles of CaO reacted with one mole of P4O10 in this reaction? A 1 B 1.5 C 3 D 6 P4Ol0 + 6CaO  2Ca3(PO4)2 Given that Ca3PO4 is the only product, write the balanced equation between P4O10 and CaO to form Ca 3PO4. Based on mole ratio, 6 moles of CaO is required to completely react with one mole of P4Ol0. Answer: D 2 Two moles of an oxidising agent, XO4− in the presence of excess acid oxidised 96 dm3 of nitrogen dioxide gas at room temperature and pressure to NO3−. What is the number of moles of electrons accepted by one mole of XO4−? A 1 B 2 C 3 D 4 n(NO 2) = 96/24= 4 NO2 + H2O NO3- + 2H+ + e XO4− ≡ NO2 2 : 4 1 : 2 2 mol of NO 2 donate 2 mol of e which is accepted by 1 mol of XO4−

2 © ACJC 2018 9729/01/Prelim/2018 [Turn over 3 Use of the