What affects the decomposition of Hydrogen peroxide?

After adding the hydrogen peroxide to the Manganese IV oxide in the conical flask, I will measure how long it takes to produce 50cm3 of oxygen using a beurette. I could have chosen the following variables:

• Amount of oxygen produced in a certain time
• Length of time to produce a certain amount of oxygen

I chose the latter because it is far more accurate and suitable for this experiment. I shall carry out two separate tests to make sure there are not any false results. I shall perform many tests for a varied concentration ranging from 0% and 20% hydrogen peroxide (as this is the highest concentration I am able to get hold of)

Prediction:

 I predict that the higher the concentration level of the hydrogen peroxide is the higher the reaction rate. This is because there is more chance of the hydrogen peroxide molecules colliding with manganese IV oxide molecules, because there are many hydrogen peroxide molecules.

Equipment:

• Water Bath
• Conical Flask
• Delivery tube
• Burette
• Hydrogen Peroxide
• Manganese IV Oxide
• Scale
• Stopwatch

Method:

1. Set up apparatus as pictured.
2. Measure 20 x 1gram trays of manganese oxide.
3. To measure solutions:                        For 20% - 100ml of Hydrogen Peroxide

                 0ml of water

For 17.5% - 87.5ml of Hydrogen Peroxide

                   12.5ml of water

For 15% - 75ml of Hydrogen Peroxide

                25ml of water

For 12.5% - 62.5ml of Hydrogen Peroxide

                   37.5 ml of water

For 10% - 50ml of Hydrogen Peroxide

                 50ml of water

For 7.5% - 37.5ml of Hydrogen Peroxide

                 62.5ml of water

For 5% - 25ml of Hydrogen Peroxide

              75ml of water

For 2.5% - 12.5ml of Hydrogen Peroxide

                 87.5ml of water

For 0% - 0ml of Hydrogen Peroxide

              100ml of water

4. Put 20% solution into the conical flask.
5. Add 1 gram of manganese IV oxide.
6. Place bung into top of the conical flask.
7. Immediately start stop watch
8. When the gas produced reaches 50 cm3 on the burette stop timing.

Safety:

This experiment is rather safe, but some precautions should be made:

• Wear safety goggles at all times, as some of these compounds involved in the experiment are harmful, and could cause damage to the eye.
• Wear gloves at all times, as some of the chemicals used may damage the skin.

Results:

                        Test Number

Conclusion

This shows that my predictions were clearly correct. There was one anomaly in test 1 for 10% hydrogen peroxide. However, when I averaged the results out they showed what I had expected; the higher the concentration, the higher the reaction rate. This is because there is more chance of the hydrogen peroxide molecules colliding with manganese IV oxide molecules, because there are many hydrogen peroxide molecules. Although the enzyme was used in the reaction, it is not chemically involved in the decomposition of hydrogen peroxide.

Evaluation

I think that the experiment was performed well and produced good results. The experiment was mostly fair; all of these were kept constant:

• Catalyst
• Amount of catalyst
• Temperature of hydrogen peroxide
• Temperature of catalyst

The temperature of the room may have changed during the time of which we carried out the experiment. To make sure this does not happen if I do it again I will measure the temperature throughout the experiment.