Conclusion:
The reaction was at its fastest, when the concentration of the hydrogen peroxide was 20 vol (100%). Here there were the largest number of substrate molecules to react with the enzymes; therefore there was a greater volume of oxygen and water produced. The rate increased steadily from 19.67cm oxygen collected, to 77.67cm collected, until there was no more enzymes left for the substrate to react with, hence the graph gradually levelling out. Other factors such as increasing the temperature and increasing the enzyme concentration would increase the rate even more if used along side the increase in substrate concentration. However as these were kept constant throughout the experiment, they prevented any further increase in the rate of reaction. The rate increases when there is an increase in the concentration of the substrate, because of the collision theory. There is an increase in the substrate (hydrogen peroxide) therefore more collisions between the substrate and the enzyme (yeast) can take place, causing the rate of reaction to increase, and the activation energy (amount of energy needed for the reaction to take place) to decrease.
…