ACJC H2 Chem 2012 Prelim P2 QP

© ACJC 2012 9647/02/Prelim/12 [Turn over Index No. Name Form Class Tutorial Class Subject Tutor ANGLO-CHINESE JUNIOR COLLEGE DEPARTMENT OF CHEMISTRY Preliminary Examination CHEMISTRY 9647/02 Higher 2 Paper 2 Structured Questions 22 August 2012 2 hours Candidates answer on the Question Paper Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, index number, form class, tutorial cl ass and subject tutor’s name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or co rrection fluid. Answer all questions. A Data Booklet is provided. The number of marks is given in brackets [ ] at the end of each question or part question. At the end of the examination, fasten all your work se curely together including the cover page. For Examiner's Use Question no. Marks 1 2 3 4 5 6 7 TOTAL This document consists of 22 printed pages and 1 blank page 9647/02/Prelim/12 ANGLO-CHINESE JUNIOR COLLEGE © ACJC 2012 Department of Chemistry [Turn over

2 © ACJC 2012 9647/02/Prelim/12 [Turn over 1 Planning (P) A student is interested to determine the Faraday co nstant. He proposed that the value of the Faraday constant can be determined experimentally using the electrolysis of aqueous nickel (II) sulfate. The student did some research and made the following notes. General information • Reaction at the cathode: Ni 2+ (aq) + 2e → Ni (s) • Reaction at the anode: Ni (s) → Ni 2+ (aq) + 2e • 1 mol of Ni (s) is deposited at the cathode by 2 m ol of electrons. • The Faraday constant is the charge in coulombs, C, carries by 1 mol of electrons. • The Faraday constant = 96500 C mol -1 Experimental setup The experimental setup for the electrolysis of nick el (II) sulfate solution is shown above. The student will electrolyse some nick el (II) sulfate solution using nickel electrodes. Before the nickel cathode is placed into the electrolyte, it will be cleaned and weighed. The current that passes through the electrolyte wil l be kept constant at 0.3 A for 40 min by adjusting a variable resistor in the experiment. At the end of 40 min, the nickel cathode will be weighed. The experiment will be repeated for another 7 times at 40 min intervals. For Examiner’s use

3 © ACJC 2012 9647/02/Prelim/12 [Turn over (a) Based on the information given under experimental s etup, give a full description of the procedures you would use in Step A