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The breakdown of hydrogen peroxide and how I can change the rate of reaction by altering the temperature.

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Introduction I will be investigating the breakdown of hydrogen peroxide and how I can change the rate of reaction by altering the temperature. To do this I will be using celery. This enzyme (a biological chemical made by a living cell) contained in celery, the catalyse will speed up the decomposition of the hydrogen peroxide so that the reaction can be monitored in class. The celery will also be liquidised as this gives a greater surface area and will mean a quicker reaction to be monitored in the time given for the experiment. As with a greater surface area of solid, collisions are far more frequent. As there are more collisions the reaction rate is greater. Diagram This diagram will be used to measure how quickly 10ml of oxygen is produced from the reaction when the hydrogen peroxide is at different temperatures. Thus being the reactor. The oxygen is one of the products, the other being water. The reaction taking place is. 2H2O2 2H2O + 02 Safety Safety points to remember are: * Wear safety goggles, as hydrogen peroxide can be dangerous. * If hydrogen peroxide has contact with my skin I will wash it immediately. * When heating the small beaker of hydrogen peroxide on a hot plate, label the beaker so it does not become a hazard. * Place hot plates in a safe and secure area to avoid burning oneself. ...read more.


The equipment will be cleaned to affect contamination from previous substances. Information Gained We had two lessons before the experiments to gain background information. Such as the 'lock and key mechanism.' Information like this had to be gained so that it was possible to find a way to gain results during lesson time. The 'lock and key mechanism' is when the enzyme (celery) and its substrate (hydrogen peroxide) meet. The substrate is the substance on which the enzyme does its work. The substrate and the enzyme must fit together in the way that a lock and its key fit together. On the surface of the enzyme, the substrate is changed to some other compound (in this case Oxygen.) The new compound separates from the enzyme. And so the enzyme is again free to combine with another molecule of the substrate. This can happen again and again. Such information like this was available through text books called "Hunt and Sykes" We also looked into the body and at the temperature at which the enzymes work. The body temperature being 37?C. Predictions and Reasons Through information gained in lessons and background knowledge I predict that as the temperature of the hydrogen peroxide increases so will the amount of oxygen produced, and should work at its best at around 37?C, as this is the temperature at which the enzymes in our body work at. ...read more.


When averaging I used these results, which could of made the average either lower or higher than it should be. To improve this I should have missed these results. Not including some sets of results when making averages may have led to better values. My results are in line with those I predicted. Graphs indicate rise in temperature up a point leads to an increase in oxygen production. This is in line with kinetic theory. However it is very clear that after a certain temperature is reached the enzyme actually virtually stops. This supports my theory of lock and key fit. However optimum activity of enzyme is at about 37�C this is as we expected. This could have been proved more clearly if I had used the temperature of 37?C in my results. But at 65�C the enzyme is still not denatured according to my results. This is a higher temperature than I would expect. Possible not allowing solutions to reach temperatures selected has led to an inaccuracy. It may be that in fact that many temperatures of solutions were lower than we stated. Overall, due to reliable repeats and in general predictions being confirmed I feel my results are reliable enough to make a conclusion. The obvious thing I would improve about the measurements I made would be to take more frequent temperatures around 65?C and 35?C temperatures to find a more accurate optimum and denatured temperatures. However I would have had to find a reliable way at keeping the temperatures as stated. ...read more.

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