Catalase is an enzyme found in many cells.
It speeds up the breakdown of hydrogen peroxide into water and oxygen.
The equation for the reaction is:
2H2O2 → 2H2O + O2
A teacher demonstrates the effect of increasing catalase concentration on the initial rate of the reaction.
This is the teacher’s method.
- Cut five equal size discs from a potato, each 0.2 mm thick
- Place the discs in a boiling tube with 5 cm3 of buffer solution
- Add 5 cm3 of hydrogen peroxide solution to the boiling tube
- Place a bung and delivery tube firmly into the boiling tube
- Position the other end of the delivery tube under an inverted measuring cylinder
- Start a timer as soon as the first bubble of oxygen enters the measuring cylinder
- Measure the volume of oxygen produced in one minute
Repeat this method three times.
The teacher uses this method with different numbers of potato discs, making sure that other conditions are unchanged.
Give the expected relationship between the named independent variable and the named dependent variable in this demonstration.