The solution will turn white because when the lipase and milk get in contact they produce fatty acids and glycerol, so the Sodium Carbonate makes the solution alkaline which is pink to start with but as more acids are produced the pH drops and the solution turns white.
Prediction
I predict that the higher the temperature, the less time the whole process will take. I think this because when there is more energy, each fat molecule will be able to find an enzyme faster so then the enzyme can break it down into fatty acids and glycerol. A higher temperature increases the amount of collisions between the substrate and the active site on the enzyme. After the enzymes are completely saturated more fats can be broken down.
Preliminary Work
We carried out some preliminary work to determine how much Sodium carbonate solution to put in. The result was that we decided to use 2cm³ because if we used 1cm³ the result would have taken too long and if we had used 3cm³ the reaction would have been to fast to time.
Fair test
To make this a fair test we will:
- Keep room temp 22 ºC must keep constant because as little as a 10ºC rise in temperature can half the time it takes the enzymes to break down the fats.
- Lipase: A higher lipase concentration will obviously speed up the time it takes to break down the fat.
- Use the same amount of ingredients.
- Make sure to stir milk as lipase is not that soluble in water and does settle out.
- Use the same timer.
Key Factors
The things that we will change are the temperature starting with 20°C and going up until we reach 70°C. The things we will keep the same are the amount of Milk, Phenolphalene, Lipase and Sodium Carbonate. We should also take into account the accuracy of measuring to ensure a fair test.
Results
We have now seen how the temperature will affect the speed of reaction as stated in my prediction. After seeing the results the time dropped as expected but not as much as I thought even though it is a sufficient amount to prove that a higher temperature reduces the time of the reaction to take pace.
The catalysts are designed to speed up reactions and that is exactly what it did producing more collisions and making the particles more energetic to react.
Evaluation
This experiment showed that as the temperature increased the time taken for the reaction to finish came down gradually. What I could have also done is to change the amount of Sodium Carbonate the same in water baths and maintain a constant temperature. I knew timing was going to be a problem and for this reason I did the experiment three times and took an average. Other similar experiments that I could have done to find out about lipase are changing the lipase concentration. Overall the experiment went quite well though my results are not completely accurate as it would have been hard to get the tube directly to the water bath as soon as possible. If we were to do the experiment again we would have taken a wider range of results to be more accurate and also keep a closer eye on the test tubes when comparing the colour change from cream to white. Another factor would have been the timing, the water baths were sometimes placed far away so the reaction could have started while the tube was in air temperature not 60 or 70 ºC. The evidence collected is quite accurate after doing 3 tests for each temperature the outcome was what I expected in our prediction. We only had 1 or 2 anomalies with the odd high or low reading because of where the water baths were placed in the room, so it was hard to get a 100% accurate experiment. Our additional preliminary work carried out helped us on deciding an important factor of the volume of Sodium Carbonate to use.