Rates of reaction - kinetics (A2)
Read our general notes on Risk Assessment
I'm currently investigating how to determine the activation energy for oxidation of iodide ions by peroxodisulphate(VI) ions in the presence of iron(III) ions as a catalyst. Would I be correct in using several experiments with temperature as a variable and the other factors kept constant, following which I plot ln(rate) against 1/T and find the gradient of the graph? How do I measure (rate)? Will the iron (III) ions play a part in my results?
Corrie writes ....
I am presuming you are using a 'clock' reaction, involving thiosulphate and starch as additional substances, and using the time for the mixture to turn black as a measure of the rate?
In which case you can use 1/time instead of rate when varying the temperature, all other things being equal.
If iron(III) ions do catalyse the reaction between iodide and peroxodisulphate, then they will certainly have an effect on the rate and hence the activation energy you find. Catalysts, by their nature, provide a route of lower activation energy for a reaction.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
back to Rates of reaction - kinetics (A2)
Rate this page or react
Share your views on this page, 3 ratings so far
, rated at 
updated: 17 August 2007
