Kinetics Practical

Procedure:

1. Place about 20cm3 of 0.02-mol dm3 solution of potassium permanganate into a beaker.
2. Add about 20 cm3 of 1.0 mol dm3 sulphuric acid.
3. Roll a small ball of iron (steel) wool.
4. Add the iron wool to the potassium permanganate and immediately start timing.
5. Using the stopwatch, measure the time taken to note a “significant “change.
6. Repeat the steps twice for two additional trials.
7. Repeat steps 1-3, however, this time use the hot plate to boil the solution.
8. Using the stopwatch leave it for two minutes.
9. Record the temperature in °C.
10. Remove the solution from the hot plate and add the iron wool to the potassium permanganate and immediately start timing.
11. Using the stopwatch, measure the time taken to note a “significant “change.
12. Repeat the steps twice for two additional trials.
13. Repeat steps 1-3, however, this time use an ice bucket as an insulator.
14. Place about 8 ice cubes surrounding the solution beaker.
15. Using the stopwatch leave it for two minutes.
16. Record the temperature in °C.
17. Remove the solution from the ice bucket and add the iron wool to the potassium permanganate and immediately start timing.
18. Using the stopwatch, measure the time taken to note a “significant “change.
19. Repeat the steps twice for two additional trials.

**Note: Stop timing when you see the dark pale colour change to a neutral transparent colour.

Data Collection:

Time taken after Temperature Change:

** Temperatures were kept constant.

Data Processing:

** Used the Average of all the times.

Overview: I chose to present my data as a scatter line graph in order for the reader to see the changes between different temperatures and also to see the difference between trails with the same temperature. You could also see the gradient Y=-0.54x+68.67, Time over temperature.

Conclusion & Evaluation:

After reviewing my hypothesis I concluded that my assumption was correct. Through knowledge gained from chemistry class I assumed that when we boil a substance or solution the particles move faster making the reaction rate increase. Therefore, when I increased the temperature using the hot plate the particles moved faster than room temperature making the significant change show rapidly. To illustrate, after calculating the average of boiled vs. Room temperature (51.43 – 33.13) you could see that there was an average difference of about 18.3 seconds. On the other hand, after I cooled the solution to change it’s temperature from 22°C to 14°C, I realized that the reaction rate took more time than room temperature. This also justifies my hypothesis, since when I calculated the average of cool vs. Room temperature (65.59 - 51.43), the average difference was 14.16 seconds. Therefore, cooling the temperature caused the particles to go slower giving it a delay compared to other warmer temperatures.

Limitations:

Some of the limitation I encountered during my experiments is:

• Only changed one factor.
• The experiment was very rushed since I tried to do three trials.
• Another limitation is I haven’t done more than three temperatures.

• Varying in temperature will help me make my conclusion more specific.

Sources of Error: