RVHS H2 Chem 2013 Prelim P2 QP

River Valley High School 9647/02/PRELIM/13 [Turn over Preliminary Examination 2013 RIVER VALLEY HIGH SCHOOL YEAR 6 PRELIMINARY EXAMINATION CANDIDATE NAME CLASS 6 CENTRE NUMBER S INDEX NUMBER H2 CHEMISTRY 9647/02 Paper 2 Structured Questions 24 September 2013 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, class, Centre number and index number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions in the space provided. A Data Booklet is provided. Do NOT write anything on it. 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. ____________________________________________________________________________ This document consists of 19 printed pages and 1 blank page. For Examiner’s Use Paper 2 Question Number 1 2 3 4 5 6 Total Marks 12 14 4 11 16 15 72 Paper 1 40 Paper 3 80 Total 192 1069

River Valley High School 9647/02/PRELIM/13 [Turn over Preliminary Examination 2013 2 1 Planning (P) Rust is mainly made up of iron ( III) oxide. An old rusty iron box can be restored by submerging the box in acid solution to remove the rust, followed by coating the iron box with a layer of metals such as chromium, aluminium or zinc using electrolysis. A student tries to adapt this process to restore a rusty iron box using only materials that are available in the school laboratory. She removed the rust on the box by submerging it in 1 mol dm 3 sulfuric acid. Then she coats the rust free box with a layer of copper using electrolysis. The diagram below shows part of the experimental set up. (a) Write a balanced equation, including state symbols, for the reaction that removes rust from the box using sulfuric acid. [1] (b) Other than safety issues, what is the disadvantage of using strong acid to remove rust from the box? [1] 1 A A 11 variable resistor +  1070

River Valley High School 9647/02/PRELIM/13 [Turn over Preliminary Examination 2013 3 (c) Complete and label the diagram abov e to show the experimental set- up for coating the rust free box with copper metal by electrolysis. Give the composition of a suitable electrolyte. [2] (d) Write the equation for the reaction at the anode and cathode. Cathode: Anode: [1] (e) The variable resistor can be used to vary the current that is passed through a closed circuit. Predict how does the amount of copper deposited in a fixed duration (t) varies as current is increased from 0.00A until 1.00A. Display your prediction in the form of a sketch