Chemistry paper exam questions 1

Question 1

Why did the student carry out an experiment three times [1]

Answer 1

to show that the experiment was more repeatable

Question 2

what did the student do with the anomalous result[1]

Answer 2

did not use it

Question 3

what conclusion can be made as the temperature increases[1]

Answer 3

increases the rate of the reaction up to 30 degrees Celsius

Question 4

At which temperature was the catalase denatured [1]

Answer 4

60 degrees Celsius

Question 5

The student thought the optimum temperature for catalase activity was between 30 degrees Celsius and 40 degrees Celsius. How could the investigation be improved to find a precise value for the optimum temperature [1]

Answer 5

do the experiment at 30 degrees Celsius 35 degrees Celsius and 40 degrees Celsius

Question 6

Amylase is the enzyme that controls the breakdown of starch to glucose
Describe how the student could investigate the effect of ph on the breakdown of starch by amylase

Answer 6

• The break down The breakdown of starch by amylase at different PHs.
  The amylase will break down the starch.
  A sample is removed from the test tubes every 10 seconds to test for the presence of starch. Iodine solution will turn a blue/black colour when starch is present, so when all the starch is broken down, a blue-black colour is no longer produced. The iodine solution will remain orange-brown.
  A control experiment must be set up - without the amylase - to make sure that the starch would not break down anyway, in the absence of an enzyme. The result of the control experiment must be negative - the colour must remain blue-black - for results with the enzyme to be valid.