Rates of reaction - kinetics (A2)
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For my A2 chemical investigation I did the reaction between iodine and propanone. I have varied the concentration of my reactants, stopping the reaction at 5 min time intervals with sodium hydrogen carbonate, before titrating with sodium thiosulphate.
I have repeated each three times and worked out an everage titre.
I don't know how to work out the concentrations of my reactants - iodine, propanone and sulphuric acid - to plot a concentration vs time graph to find the order of the reaction with respect to my reactants.
Corrie writes ...
You don't need to! The volume of the thiosulphate titre is proportional to the iodine concentration. So you can plot Vthio vs time. The shape of this graph will show you the order with respect to iodine, presuming the propanone and acid are present in large excess - and therefore do not change significantly during the reaction. You should get an interesting plot - and order - for iodine!
Then you change the propanone or acid concentration and repeat experiment and the plot. The line will have a new slope - remember the slope represents the rate. The change in slope should tell you the effect of the change in propanone or acid concentration on the rate, and hence the order.
Repeat this all for the last reactant. You should then have all three orders.
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updated: 17 April 2007
