Investigating what affects the rate of reaction of Catalase and potato.

                            One piece                        5 pieces

                       Of potato                        of potato

                   = Hydrogen Peroxide

As you can see, the collisions are a lot more frequent in the 5 pieces of potato than in the single piece.

This can plotted on a graph, as below:

Graph showing the rate of reaction increasing as the surface area increases

                Rate of reaction

Surface area

Apparatus:

• Beaker
• Tile (for cutting the potato on)
• Scalpel
• Test Tubes
• Measuring Cylinder
• Potato
• Hydrogen Peroxide
• Delivery tube

Potato

Hydrogen Peroxide

The below diagram shows how the apparatus should be set up:

          Delivery tube

      Bung

                      Potato                                                Test Tube

                                        Oxygen Bubbles

Method: 

        First I will take a potato and cut it into 5 equal cylinders. I will then cut one of these into 2 equal pieces, another into 3 pieces, another into 4 pieces and one I will leave whole. I will fill a test tube up with water, then I will put 50cm³ of Hydrogen Peroxide into another. I will put the first potato into the Hydrogen Peroxide, and then put a delivery tube from the water to the potato. I will count the bubbles coming off of the potato, which is the oxygen from the hydrogen peroxide and Catalase reacting together. I will time the reaction, and count the bubbles produced in a minute. I will repeat this for all the different sets of potatoes. To make sure it is kept a fair test I will sue the same amount of Hydrogen Peroxide in each test and I will need to keep the temperature the same.

Results:

Conclusion:  

        As you can see, the number of bubbles does increase as the surface area does. This is because as I stated in the hypothesis there is more chance of a successful collision between the potato and the Hydrogen Peroxide. This results in more Catalase reacting with the Hydrogen Peroxide. As they react together, oxygen is made and this is released in the bubbles I counted in the second tube.  There were no anomalous results and they results we got were fairly accurate.

Evaluation: 

The experiment was not carried out to be totally exact. When cutting then pieces of potato, it was only accurate to our eyes, and to a ruler, and then it was only 1mm. We could have used a more accurate device to measure the potato. We could also have investigated other things that affect the rate of reaction, such as temperature, concentration of the reactants, and the use of a catalyst. This would have given me a larger understanding of the rate of reaction. I could also have made the test fairer by monitoring the temperature of the solutions I was using, rather than taking them all as room temperature without checking

Bibliography:

Chemistry by Hunt and Sykes.

Letts GCSE science

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