RI_H2_Chem_P2 Prelim

1   © Raffles Institution 9647/02/S/14 [Turn Over RAFFLES INSTITUTION 2014 YEAR 6 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS INDEX NUMBER CHEMISTRY 9647/02 Paper 2 Structured Questions 17 September 2014 2 hours Candidates answer on the Question Paper. Additional Materials: Data Booklet READ THESE INSTRUCTIONS FIRST Write your name, class and index number in the spaces provided at the top of this page. Write in dark blue or black pen in the spaces provided. 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. A Data Booklet is provided. Do not write anything on it. You are reminded of the need for good English and clear presentation in your answers. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 / 12 2 / 10 3 / 12 4 / 14 5 / 24 Total / 72 This document consists of 19 printed pages.

2 © Raffles Institution 9647/02/S/14 [Turn Over 1 Planning You are to plan an experiment to investigate how the rate of the reaction between propanone and iodine, catalysed by dilute sulfuric acid, depends on temperature and to calculate the activation energy, E a, for the reaction. When excess propanone and iodine react in the presence of dilute sulfuric acid, iodine is decolourised and the brown solution becomes colourless when iodine is used up. In the reaction, one of the hydrogen atoms in propanone is replaced by an iodine atom and hydroiodic acid is produced. (a) Construct a balanced chemical equation for the reaction. …..……………………………………………………………………………..………..… [1] A teacher demonstrates this experiment as follows. She prepares two separate solutions, X and Y. Solution X contains 5.00 g dm 3 iodine solution. Solution Y is a mixture of 500 cm 3 of 1.0 mol dm 3 propanone and 500 cm 3 of 1.0 mol dm3 dilute sulfuric acid. She mixes 10 cm 3 of solution X with 10 cm 3 of solution Y at 35 oC and, after 40 seconds, the mixture decolourises. (b) Consider the description of the experiment given above. The dependence of the reaction rate on temperature may be determined by performing a number of experiments at different temperatures. You may find it useful to use 1/t to represent the reaction rate, where t is the time taken for the reaction mixture to decolourise. (i) Draw a labelled diagram of the experimental setup you would use to carry out this experiment. You should use only standard apparatus found in a school laboratory and show clearly the following:  the apparatus used as the reaction vessel  how the the