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How will Concentration affect the Volume and Rate of Oxygen Released when reacting Hydrogen Peroxide with a Potato

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How will Concentration affect the Volume and Rate of Oxygen Released when reacting Hydrogen Peroxide with a Potato Introduction I am going to find out whether the concentration of hydrogen peroxide (H2O2) will affect the rate and volume of oxygen produced by a potato when hydrogen peroxide is added to it. Plan Potatoes contain a chemical enzyme called catalase to break down poisonous hydrogen peroxide into harmless water and oxygen. Hydrogen peroxide is produced in certain cell reactions. Without catalase, the potato would not be able to break it down, and the organism would die. The chemical equation for this reaction is: catalase 2H2O2 2H2O + O2 Enzymes are biological catalysts. They are: * Catalysts: they are substances that speed up reactions, without being disfigured or used up themselves. This makes them very useful, because even small amounts can do a big job. * Proteins: They have a special shape for each specific substance it works on. I will now show as diagram how they are specific. As you can see enzyme A can only react with substance a, and not c. However, enzyme C will not react substance a only c. The substance on which an enzyme acts is called its substrate. Catalase is a biological enzyme. It is found in foods because it speeds up the disintegration of hydrogen peroxide into water and oxygen as you can see in the above equation. It is able to do this because hydrogen peroxide has a shape that aids the decomposition of it by catalase. This is shown in the diagram above. This type of reaction is called an anabolic reaction. An anabolic reaction is when large molecules are built from smaller molecules. In this case, hydrogen peroxide is a small molecule and when reacted with catalase water is produced which is a bigger molecule. There are four factors that affect the rate at which an enzymes works: 1. ...read more.


oxygen (cm3) 90 (s) oxygen (cm3) 120 (s) oxygen (cm3) 150 (s) oxygen (cm3) 180 (s) oxygen (cm3) 210 (s) oxygen (cm3) 240 (s) oxygen (cm3) 270 (s) oxygen (cm3) 300 (s) oxygen (cm3) 40 0 0 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.4 40 0 0 0.3 0.6 0.9 1.2 1.4 1.6 1.9 2.1 2.4 2.5 30 10 0 0.2 0.9 1.2 1.4 1.6 1.8 1.9 2.0 2.1 2.1 30 10 0 0.5 0.7 0.9 1.1 1.4 1.6 1.7 1.8 2.0 2.1 20 20 0 0.9 1.2 1.5 1.8 2.1 2.4 2.6 2.8 3.0 3.1 20 20 0 0.1 0.6 0.7 0.9 1.1 1.2 1.3 1.4 1.5 1.6 10 30 0 0.5 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 10 30 0 0.5 0.6 0.8 1.0 1.1 1.2 1.3 1.4 1.6 1.7 As you can see, I have tabulated my results clearly. I have repeated some of the results because I noticed some rogue points appearing. In addition, I have repeated each concentration twice so that I can average out any rouge points that I have not noticed already. This will help the accuracy of my results. I feel that these are high quality results because they seem to agree with my plan, and hypothesis. I will now draw graphs to see whether my initial reactions to these results are correct. I feel I have made enough observations and measurements including repetitions to obtain reliable evidence. I am drawing a graph to see whether my results fit a certain trend, which I mentioned in my plan. I will now make a table of averages, which will average out any rogue points in my results. Concentration Peroxide (Volume) Concentration Water (cm3) 0 (s) oxygen (cm3) 30 (s) oxygen (cm3) 60 (s) oxygen (cm3) 90 (s) oxygen (cm3) 120 (s) oxygen (cm3) 150 (s) oxygen (cm3) 180 (s) oxygen (cm3) ...read more.


I would have liked to use an instrument that would allow me to add the potato and quickly close bung. For example, a hole in the bung where you can add the potato and then rapidly replace the cap over the hole. I would also have liked to have a way of places the delivery tube inside the measuring cylinder in the water bath quickly, so that no oxygen is lost while doing this. In addition to this, water went into the tube while I was trying to get the delivery tube into the measuring cylinder. It took time for the first bubble to arrive. I think this could have hampered my results because there would be a bunch of bubbles together in the tube trying to push the water out, this would affect my results concerning the rate. I feel tat the water bath was too small, and a larger one would allow more room for the hand to reach under the measuring cylinder and insert the delivery tube. To obtain further evidence I would allow the oxygen to completely stop coming out of the potato, so I can measure the rate better, and am able to recognise more points that are anomalous. This would give me further evidence and allow me to write a firmer conclusion. To extend the investigation I would see how much affect the temperature and the surface area have on the rate of oxygen released. I would measure the temperature by having a heated water bath, which would keep the test tubes at constant temperature. I would use the same concentration of hydrogen peroxide along with potato pieces of the same mass and surface area, and place them in differing temperatures. I could then draw a graph of rate of reaction vs. temperature. To measure the surface area I could measure the surface of each potato piece using callipers and see whether different surface area of potato pieces in a constant concentration of hydrogen peroxide give different rates of reaction. Jay Vyas 11CK ...read more.

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