Sorry - I have now decided to:
1. Measure the half life of the reaction using 0.20g of manganese (IV) oxide - I kept this amount of catalyst constant wen changing h202 and temperature.
2. Measure the half life of the reaction using 0.02g of lead (IV) dioxide - Same reasons as above.
3. Then because i have data for 0.40, 0.60, 0.80g, I will see how changing the amount of catalyst - affects the rate of the reaction - so just measure the volume of oxygen produced for 10 times. Draw a graph and then calculate the rate, and i shud find that as I increase the amount of catalyst, the rate increases, possibly due to the fact there a there is more catalyst, more reactants should become adsorbed.
Will that be right? None of the teachers are answering their e-mails!
Thank you if the above is right, then I have no more questions! You have been a great help