Purpose
To test the effect of a catalyst (nothing, CuCl2, NaCl, KI) on the rate at which hydrogen peroxide decomposes
Hypothesis
If the rate at which hydrogen peroxide decomposes is related to the presence of a catalyst, then the more reactive the catalyst the faster the rate at which hydrogen peroxide decomposes
Independent variable: Presence of a catalyst
Dependent variable: The rate at which hydrogen peroxide decomposes
Controlled variables: Amount of Catalyst solution
Temperature of reactants
Amount of Hydrogen Peroxide
Materials
- Hydrogen Peroxide
- 10 mL of CuCl2
- 10 mL of NaCl
- 10 mL of KI
- Beaker
- Graduated Cylinder
- Funnel
- water
- stopwatch
Procedure
1. Put Hydrogen Peroxide into 100 mL of water and record the time it takes for the hydrogen peroxide to decompose completely.
2. Dispose of the waste properly and rinse the beaker thoroughly.
3. Repeat Steps 1-2 for the 2nd trial
4. Calculate the mean between the two times
5. Put 10 mL of CuCl2 into a beaker with 100 mL of water
6. Put Hydrogen Peroxide into the mixture and record the time it takes for the hydrogen peroxide to decompose completely.
7. Dispose of the waste properly and rinse the beaker thoroughly.
8. Repeat Steps 5-7 for the 2nd trial
9. Calculate the mean between the two times
10. Put 10 mL of NaCl into a beaker with 100 mL of water
11. Put Hydrogen Peroxide into the mixture and record the time it takes for the hydrogen peroxide to decompose completely.
12. Dispose of the waste properly and rinse the beaker thoroughly.
13. Repeat Steps 10-12 for the 2nd trial
14. Calculate the mean between the two times
15.Put 10 mL of KI into a beaker with 100 mL of water
16. Put Hydrogen Peroxide into the mixture and record the time it takes for the hydrogen peroxide to decompose completely.
17. Dispose of the waste properly and rinse the beaker thoroughly.
18. Repeat Steps 15-17 for the 2nd trial
19. Calculate the mean between the two times.
Discussion
In my hypothesis I stated that if the rate at which hydrogen peroxide decomposes is related to the presence of a catalyst, then the presence of a catalyst will result in a faster rate to which the hydrogen peroxide decomposes. My predictions were proved correct compared to the outcome of the experiment. In order to come to this hypothesis background research was done by our group within the, BC Science 10 textbook and other Collingwood approved databases about the presence of a catalyst.
In this experiment we tested the effect of the presence of a catalyst on the rate at which hydrogen peroxide decomposes. The control variables, the amount of catalyst solution, the temperature of reactants, and the amount of hydrogen peroxide. These remained unchanged and held constant throughout the experiment as to not allow them to invalidate the experiment.
The results were as follows; when there was no catalyst added there was no reaction, with CuCl2 (Copper II Chloride) there was a very rapid reaction with the expansion over blue foam over top of the test tube, with the addition of NaCl (Sodium Chloride or Salt) there was no reaction, and finally the KI (Potassium Iodide) resulted in a less rapid but longer reaction compared to the CuCl2 again with the expansion of orange foam over top the test tube. These results proved my hypothesis correct that with the presence of a catalyst the rate of reaction will increase.
Overall the experiment was a strong teaching point as it gave me a physical representation of the effects of catalysts providing me with a stronger knowledge of this topic. The only possible problem that was identified to me was that the reactions with the catalysts were vague and troubling to differ between the two, as the reactions were quite similar to each other only fluctuating in a few detailed aspects. However I do not believe that this problem had any other chain reactions as to falsify our experiment. To the extent of my knowledge for this course I do not believe I would change or add to the components being tested if I were to repeat this project.
Conclusion
In my hypothesis I stated that if the rate at which an Alka Seltzer tablet dissolves is related to the surface area than increasing the surface area will increase the rate at which the Alka Seltzer tablets dissolve. In conclusion the outcome of this experiment directly relates to the research and previously believed scientific theories and explanations regarding this topic. My hypothesis was proved correct in that an increase of surface area resulted in a much faster rate of dissolve for the Alka Seltzer tablets.