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Introduction

F.6 Chemistry Experiment Date 7th March 2008 Experiment No. 15 Title Investigation of the Order of the Reaction of Iodine with Propanone Objective To investigate the order of the reaction of iodine with propanone. Introduction The rate of a chemical reaction is affected by the concentration of reactants according to the rate equation, which has to be determined experimentally. Iodine react with propanone as following: CH3COCH3(aq) + I2(aq) CH3COCH2I(aq) + HI(aq) By titrating the remained iodine in the reaction mixture against standard sodium thiosulphate solution at various times, the rate of reaction can be determined. By further varying the initial concentration of propanone while keeping the initial concentration of iodine constant, the relationship between rate of reaction and concentration of propanone can also be established. Experimental Procedure � 25.0 cm3 of sodium thiosulphate solution was diluted to 250 cm3 in a standard flask. � 25 cm3 of sulphuric acid, V1 cm3 of propanone solution and V2 cm3 of distilled water was measured using a ...read more.

Middle

� After 10, 15, 20, 25 and 30 minutes, 10 cm3 portions of the reaction mixture was withdrawn further from the flask and the above procedure was carried out each time. Results Time when the reation mixture was added to NaHCO3 / min 5 10 15 20 25 30 Final burette reading / cm3 20.12 18.00 16.40 14.74 13.11 11.80 Initial burette reading / cm3 00.02 00.00 00.00 00.04 00.01 00.00 Volume of Na2S2O3 used / cm3 20.10 18.00 16.40 14.70 13.10 11.80 Pair No. A B C D Gradient of Graph 1 / cm3 min-1 0.282 0.257 0.189 0.123 Conclusion The gradient of graph 1 is -0.33 and that of graph 2 is 0.010. As the reaction rate in does not change with the decreasing concentration of iodine, the order of reaction with iodine is 0. As the reaction rate increases with the concentration of propanone, the order of reaction with propanone is 1. ...read more.

Conclusion

of moles of S2O32- = 2 x 0.0001 = 0.0002 mol Volume of sodium thiosulphate = 19.7 cm3 Concentration of S2O32- = ( 0.0002 x 10 ) / ( 19.7 / 1000 ) = 0.102 M Discussion The temperature during the experiment is not constant, it affects the rate of reaction and thus the result. To improve the experiment, some known amounts of reactants are placed in a thermostatic bath for several minutes to allow the temperature of the reactants to reach the temperature of the thermostatic bath. Also the experiment was not conducted accurately, as pipette was not used as often as it should have been. To improve the experiment, pipette should be used to deliver the reaction mixture into the conical flask A colorimeter could be used to provide the most accurate result. Moreover, repeat the titration several times can also eliminate the effects bought by error. For further investigation, we can investigate the effect of temperature on the order of the reaction of iodine with propanone by allowing iodine react with propanone at different temperature. Reference http://qcrc.qef.org.hk/proposal/2000/2000-1245/2000-1245-D04-32143.DOC Lab menu ...read more.

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