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This experiment examines how the concentration of hydrogen peroxide affects the rates of reaction of the enzyme catalyse. Catalyse is found in liver and potato in this experiment I will be using potato as my catalyse source.

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Does concentration increase reaction time?

This experiment examines how the concentration of hydrogen peroxide affects the rates of reaction of the enzyme catalyse. Catalyse is found in liver and potato in this experiment I will be using potato as my catalyse source.

Prediction

I predict the more concentrated the hydrogen peroxide is the quicker the reaction time will take place. This means the gas syringe will fill with gas more quickly I will know if my prediction is right if after 3 minutes the tube is more full of gas when the peroxide is more concentrated then it is after three minutes of the less concentrated solution.

Equipment

  • Gas syringe
  •  Clamp and stand
  •  Potato
  •  Hydrogen Peroxide
  •  Test Tubes
  •  Beakers
  •  Stop Watch
  • Pipette
  • Measuring cylinders
  • Distilled water
  • Electric scales

Preliminary

Before I conduct my main experiment I must carry out a preliminary which will help me to understand the investigation on a whole.  This will help me to make decisions for my final investigation such as how much grams of potato to use and how long to set the stop clock for before  I record my results. I will be testing how much oxygen is produced by the reaction between catalyse in potato and hydrogen peroxide. I will vary how much the hydrogen peroxide is diluted and compared at the end how the concentration of hydrogen peroxide increases the reaction time.

Dilution of Hydrogen Peroxide

First I have to dilute the hydrogen peroxide properly this is done using a formula the formula is:

C1V1 = C2V2

I decide that I will investigate with 5 different dilutions. My first 1 will be 10% concentrated

Concentration 10% Concentration 20%

C1V1 = C2V2                                                        C1V1=C2V2                      

C1=80% AND C2=10%                                         C1=8O% AND C2=20%

V2=60                                                                    V2= 60

80XV1 = 10X60                                                      80XV1=1200

80V1 = 600                                                             V1=1200/80

V1 = 600/80                                                            V1= 15

V1=7.5                                          

C1 Is the original concentration of the Hydrogen Peroxide which must stay the same in my equation. V1 is the amount of hydrogen peroxide I will mix in with water. V2 is the overall volume of the substance which is 60cm3. The hydrogen peroxide and water must add up to 60cm3 to make this a fair test so my next step was to take 7.5 away from 60, to let me know how much water to add to the peroxide. I did these few steps five times for my five different dilutions and ended up with this table:

Concentration %

Volume of H2O2

Volume of H20

10

7.5

52.5

20

15

45

30

22.5

37.5

40

30

30

50

37.5

22.5

These are the measurement I will be using in my experiment.

Method

  • First I collected my equipment
  • Next I put on some gloves and safety goggles to protect my hands and eyes from the chemicals
  • Then I attached the clamp to the stand and the gas syringe to the clamp horizontally
  • Next I measured out the hydrogen peroxide into a measuring cylinder an then poured it into a beaker
  • Next I measured out the water in another measuring cylinder then I added the water to the hydrogen peroxide
  • Then I used a metal tube to remove an equal amount of potato
  • I weighed the potato to exactly 2.8g and placed it in a test tube
  • Next I added 15cm3 of the hydrogen peroxide to the test tube and immediately attached it to the gas syringe and started the stop watch
  • While waiting for the timer to reach 3 minutes  I held the tube up right
  • When the test tube reached 3 minutes I read the syringe to see how much oxygen the reaction had produced and wrote down my results
  • I repeated this two more times and moved on to the next concentration.

Results

% of hydrogen peroxide

Volume of hydrogen

peroxide

Time

Volume Of  Oxygen

Hydrogen peroxide

Water

1

2

3

Average

10

7.5

52.5

3

0

0.5

0.3

0.26

20

15

45

3

0.4

0.1

0

0.16

30

22.5

37.5

3

0

0.2

0.3

0.16

It was important to do a preliminary as these results were obviously the results were all about the same and the gas syringe had hardly moved.  I decided to change the amount of potato as it was the one of the factors that were kept the same. I increased the amount of potato to 3.5g and my table looked almost exactly the same.

% of hydrogen peroxide

Volume of

hydrogen  peroxide

Time

Volume Of Oxygen

Hydrogen peroxide

Water

1

2

3

Average

10

7.5

52.5

3

0.1

0.2

0.1

0.13

20

15

45

3

0.3

0

0.4

0.175

30

22.5

37.5

3

0

0.2

0.2

0.13

These results were clearly wrong as other groups results were much larger and showed a variety and difference between each dilution.

Main experiment

The factors I will be controlling are:

  • the temperature of which the experiment is carried out
  • how much potato that is used
  • also the length of time

The temperature will be room temperature at roughly 25 degrees.

I will use 5g of potato as in my preliminary I found out I was using to little potato.

I will keep my time at 3 minutes as that should be enough time to see a difference.

Safety

  • I will tie back my hair to keep it out of the way
  • I will were protective gloves in case of spillages
  • I will wear protective goggles to keep my eyes safe from the chemicals

Method

  • First I collected my equipment
  • Next I put on some gloves and safety goggles to protect my hands and eyes from the chemicals
  • Then I attached the clamp to the stand and the gas syringe to the clamp horizontally
  • Next I measured out the hydrogen peroxide into a measuring cylinder an then poured it into a beaker
  • Next I measured out the water in another measuring cylinder then I added the water to the hydrogen peroxide
  • Then I used a metal tube to remove an equal amount of potato
  • I weighed the potato to exactly 5g and placed it in a test tube
  • Next I added 15cm3 of the hydrogen peroxide to the test tube and immediately attached it to the gas syringe and started the stop watch
  • While waiting for the timer to reach 3 minutes  I held the tube up right
  • When the test tube reached 3 minutes I read the syringe to see how much oxygen the reaction had produced and wrote down my results
  • I repeated this two more times and moved on to the next concentration.

Results

% of hydrogen peroxide

Volume of Hydrogen

Peroxide

Time

Volume Of Oxygen

Hydrogen peroxide

water

1

2

3

Average

10

7.5

52.5

3

9.5

10

10.5

10

20

15

45

3

17

15

25

19

30

22.5

37.5

3

20

24

23

22.3

40

30

30

3

17

18

20

18.3

50

37.5

22.5

3

28

32

30

30

Conclusion

The more concentrated the hydrogen peroxide is the quicker the reaction takes place. This was my prediction and it is mostly right as the amount of oxygen increased until it got to the 40% concentrated I believe I will have to redo the 40% concentrated solution as the amount of oxygen suddenly drops when it has been increasing the whole way through the experiment. The results look more like the solution of the 20% concentrated hydrogen peroxide. I am sure that something must have went wrong during the dilution of the hydrogen peroxide and it should be retested. However on the whole the more concentrated the hydrogen peroxide is the quicker the reaction takes place.

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