Fair test
To make the test fair in the investigation we will make sure the following things are done; lastly the substances measures are done properly by checking they are on the amount stated. The person who reads the time is in line so the time is not read out wrong and finally the equipment after each experiment will be needed to get washed out thoroughly so chemicals are left in from the last experiment. If all these things are done properly then the results for the investigation will be correct.
What has not been done though to get an even more accurate result in the experiment would be to use clamping method so the amount of oxygen given of will be clearer to read.
Equipment to be changed
In this investigation I intend to change the large measuring cylinder for a small one this is so the person reading the measurements will have a more accurate scales so the sm3 indicator is clearer to read. The rest of the investigation equipment will be kept the same.
Amount of substance to be used
For this experiment the concentration of the hydrogen peroxide will be 100% with the yeast to be at 5cm3. The experiment will be done three times to get a more reliable result through finding an average from the three. It will also mean we are able to compare the three results to see if there is any results that look out of place. The time taken for each experiment will be 180 seconds (3 minutes) with there being regular intervals every 30 seconds to note down a result. This is important for the results to be noted at regular intervals as if they were not, then an average could not be made and it would be impossible to comment on the results of any great success. With there being six results taken this should be sufficient enough to explain what is being shown from the experiment to come to a correct conclusion.
Apparatus
The equipment needed for this experiment is:
X1 100cm3 cylinder (measuring)
X1 Bunsen burner tubing
X1 water bath
X1 test tube
Method
Set up the experiment as shown in the diagram.
For the experiment to work you must firstly pour water into the 100cm3 cylinder and turn it upside down ready to lose oxygen if my prediction is correct. Then you must pour 15cm3 of 100% H202 into the test tube, and as soon as 5cm3 of yeast is added and the lid is put on the timer will be started. Then every 30 seconds a result will be taken of how much oxygen has been lost from the measuring cylinder, this happens as the oxygen pushes out the water from the reaction between the catalyse and the hydrogen peroxide. This will then complete the experiment after 180 seconds are gone and the results can be examined to be out into a results chart graph, and a conclusion to this.
Results
Analysing the evidence
The results show that any given variable of Hydrogen Peroxide will make the enzyme react. And the more concentration of hydrogen peroxide the faster rate of oxygen is given off in a chemical reaction. The trend that I can see in my results shows that with the concentration of acid at its strongest, the oxygen is given off at a rate, which is fast, but not a consistent amount each 30 seconds. The lowest concentration at 20% of H202 gives off oxygen at a lot slower rate because there are fewer molecules to collide with.
This diagram is to show that the higher concentration 100% H202 has a lot more molecules this meant when they moved around, they will have a lot more around successful collisions, making the products of water and oxygen be given off at a lot more faster rate than 20% H202.
Further information that I have looked up has been to explain the specificity of an enzyme to a certain molecule, in this case H202.
Diagram 1 shows that the enzyme and the substrate molecule (H202) are very exact. It is said that each enzyme has an active site where the substrate molecule becomes attached. The shape of the active site and the different chemicals groups within it makes sure that only a substrate molecule that has the same structure can continue. In diagram 2 the final thing develops from the effect and the product is developed. The name given to this is called the lock and key, as only a specific enzyme will open e.g. a key, a substrate molecule. This means a molecule that is only specific for one enzyme.
Conclusion
What I have found out is that the specific enzyme (catalyse) will react with H202 and, the higher concentration is of H202 the faster oxygen is given off. My statement in the prediction was correct that the catalyse will break down hydrogen peroxide into water and oxygen. The results were good as a clear understanding was easy to see and everything that I has stated in my fair test column was done correctly, to come to a conclusion that a variable on the catalyse has a affect on the rate of an enzyme reaction, and the more the concentration, the higher amount of oxygen is given off.
Evaluation
I think that the experiment has been very successful as the results obtained were very clear. There were though a few results that were to me definitely out, which were probably due to the results being read of the cylinder wrong. The results of 80% H202 was the one which has results that are slightly out, at 60 seconds and at 90 seconds which again I feel is miss read because the rest of the results finished in correlation to the other results. The 100% H202 is not inline to the others results but because so much oxygen is being given off, the results will be very high.
The thing that I would change is to clamp the measuring cylinder so the results can be read off better. I would also scale down the concentration more so less oxygen is given off so more accurate results can be achieved. Overall though the experiment has been very successful with the question of how does one variable affect an enzyme reaction being answered, with the answer of it reacting with H202 to give off oxygen and water. And further work shows that the higher the concentration of H202 the faster the amount that oxygen is given off to end this investigation.
Apparatus
The equipment needed for this experiment is.
X 1 100cm3 cylinder (measure)
X 1 a Bunsen burner tubing
X 1 water bath
X 1 test tube
Method
Set up the experiment as shown in the diagram.
For the experiment to work us must firstly pour water into the 100cm3 cylinder and turn it upside down ready to lose oxygen if my prediction is correct. Then you must pour 15cm3 of 100% H2O2 into the test tube, and as soon as 5cm3 of yeast is added and lid is put on the timer will then be started. Then every 30 seconds a result will be taken of how much oxygen has been lost from the measuring cylinder, this happens as the oxygen pushes out the water from the reaction between the catalyse and the hydrogen peroxide. This will then complete the experiment after 180 seconds are gone and the results can be examined to be put into result charts graphs and an conclusion to this
