2H 0 2H 0 + 0
Hydrogen peroxide water + oxygen
Catalysts are substances that speed up chemical reactions without being used up in the reaction. They do this by allowing the bonds to break more easily.
Chemical reactions occur when the particles of the reacting substances collide. By increasing the concentration of the reactants as we are going to do, will increase the number of collisions per second. This will increase the rate of the reaction between the hydrogen peroxide and the liver solution.
When one of the reactants is a solid, the reaction can only take place at the surface of the solid. Breaking the solid into smaller pieces will increase the surface area exposed to the other reactant. Dissolving the reactant in water to make a liver solution as we are going to do increases the surface area a lot and this should increases the reaction rate.
Since temperature is a measure of the motion of particles, increasing the temperature will cause the particles to move faster. When particles move faster, more collisions occur and the collisions are more violent. This should increase the reaction rate.
(Information taken from www.learn.co.uk)
Apparatus:
Method:
- We are measuring the change in temperature as the hydrogen peroxide is dissolved by the enzymes in the liver solution.
- To keep it a fair test we will keep the room temperature the same throughout the six experiments and we will make sure that the concentrations that are used total 20ml for each experiment.
- The variables that will be changed are the concentrations as shown in the table above.
- We would have liked to have repeated each experiment three times so as to take an average reading which would give a more accurate reading, however the time limit does not allow us to do this.
- We will keep it a safe investigation by wearing goggles at all times.
- We will record our results by recording the temperatures on a data logger, then transferring them to a computer so as to use them to produce graphs.
Results:
See the following six pages.
Conclusion:
After collecting my results and drawing the graphs seen previously I can see that as the concentration of hydrogen peroxide increases so does the rate of reaction. The temperature on the graphs shows the rate of reaction. For the experiment with 0% hydrogen peroxide the maximum temperature reached was approximately 17 degrees Celsius, whereas the experiment for 100% hydrogen peroxide has a maximum temperature of approximately 30 degrees Celsius. This shows that higher the temperature the quicker the rate of reaction.
These results show that my prediction was correct and that the higher the concentration the quicker the rate of reaction. This happens as the liver contains the enzymes catalyse which speed up the rate of reaction without being used up in the reaction. They do this by allowing the bonds to break more easily.
Also chemical reactions occur when the particles of the reacting substances collide. By increasing the concentration of the reactants we are increasing the number of collisions per second. This increased the rate of the reaction between the hydrogen peroxide and the liver solution.
When one of the reactants is a solid, the reaction can only take place at the surface of the solid. Breaking the solid into smaller pieces will increase the surface area exposed to the other reactant. Dissolving the reactant in water to make a liver solution as we did increased the surface area and increased the reaction rate.
Evaluation:
After completing this experiment I feel that my results weren’t as accurate as they could have been as we only carried the experiment out once. If time had allowed, I would have liked to have repeated the experiment three times and taken an average reading, rather than relying on one set of results to be accurate.
I don’t think that I got any odd results as all my graphs increased in temperature as the concentration increased.
If I were to carry out this experiment again I would like to use a different reactant in place of the liver to see if the same results occur.
I think the results are sufficient to support a firm conclusion, as I don’t feel there where any odd results and that the recording of the results was very accurate due to the type of apparatus used to measure the temperature.
To extend this experiment I would like to investigate the other factors that affect the rate of reaction. For example the surface area, or the temperature at which the experiment is carried out.
