8 mark science questions help

Keep the phenolpthalein solution away from naked flames as it is flammable.

Wear eye protection and quickly rinse any splashes of enzyme solution or sodium carbonate from skin as it is an irritant.

Make sure you know what to do if the thermometer is broken. So, if it breaks then you should sweep up into a glass bin and if glass gets in your fingers you should seek medical attention.

1. Set up 5 water baths at temperatures of 10,20,30,40, and 60 degrees

2. Add 2cm3 of lipase into a test tube and label the side with a temperature and place it into the corresponding water bath

3. Lable a boiling tube with the temperature you will be investigating

4. Add 5 drops of pheonlphtalein to the boiling tube

5. Measure out 5cm3 of milk using a measuring cylinder and add this to the boiling tube

6. Measure out 8cm3 of sodium carbonate solution and add this to the boiling tube. To the same test tube add 3cm3 of PH7 buffer.  (should be pink)

7. Place thermometer into the boiling tube

8. Place the tube into the water bath and leave until the contents reach the same temp as the water bath

9. Remove the thermometer from the test tube and replace with a glass rod

10. Measure out 5cm3 of the solution and add it to the lipase solution

11. Stir the contents of the solution until it loses its pink colour

12. Stop the stop clock and note the time it took to become colourless then plot in a table

13. PLot a graph of the time taken for the reaction to occur against temperature

14.You can convert this to a rate of reaction graph by calculation 1 divided by time for each of the temperatures

Independent variable = Temperature

Dependent variable = Time taken for solution to change from pink to white

Control variable = PH buffer, volume of sodiu hydroxide solution, volume of milk, volume of lipase and age of the enzyme

Hypothesis --> As the temperature increases, the rate of reaction will increase, up til the optimum. Afterwards, the rate of reaction will decrease as the enxume is denatured.