area that permits the reaction to go faster because the substrate molecules can get to the enzyme molecules faster and more efficiently.
             The reaction will be timed as soon as the solution (H2O2 and H2O) is added. The oxygen that evolves will be measured and recorded every 30 seconds until the reaction finishes.
             The concentration of the solution will be variegated in the experiment. This is the only element that is varied everything else must stay the same to keep the investigation unbiased. 25cm3 of solution was chosen to be used because in the pilot experiment this was all that was necessary to produce a sufficient amount of oxygen in the gas syringe so that it could be easily measured. If there were more solution it would take longer to pour in to the conical flask therefore gas would escape before the rubber bung could be fixed into place to seal the conical flask. If less solution were to be used the reaction would take longer because there wouldn't be as many substrate molecules to react with the enzymes.
             The solution will be measured in a measuring cylinder. The range was selected because it is easily multiplied into 100, which is what is needed to calculate percentages. The measuring cylinder was chosen to be used over all other methods of measuring because it is easily available.
             Percentage of H2O2 Volume H2O2 (cm3) Volume of H2O(cm3)
             The enzyme catalase works best at a warm temperature so to speed the experiment up the conical flask will be in a water bath at the temperature range 40-45 oC. The water bath needs to be kept at a constant temperature because the enzymes will then be working at the same constant rate. The mass of the potato needs to be kept the same at 4g so there is the same amount of enzyme in each experiment. The overall amount of solution needs to be kept constant to ensure that the % concentration is correct.
             The oxygen evolved will be measured every 30 seconds from the moment the solution ...