Students are investigating the effect of temperature on the rate of hydrogen peroxide breakdown by the enzyme catalase.
They set up the apparatus shown below:
They perform the experiment at three different temperatures: 15 ∘C15\text{ }^\circ\text{C}15 ∘C, 30 ∘C30\text{ }^\circ\text{C}30 ∘C, and 45 ∘C45\text{ }^\circ\text{C}45 ∘C.
As catalase breaks down hydrogen peroxide, oxygen gas is released. The students measure the volume of oxygen gas produced in the first 222 minutes.
State whether the "volume of oxygen gas produced in 2 minutes" is the independent, dependent, or control variable.
Complete the following sentences to explain why the rate of hydrogen peroxide breakdown is greater at 30 ∘C30\text{ }^\circ\text{C}30 ∘C than at 15 ∘C15\text{ }^\circ\text{C}15 ∘C:
- Hydrogen peroxide decomposes ‾\underline{\quad\quad\quad\quad} at 30 ∘C30\text{ }^\circ\text{C}30 ∘C than at 15 ∘C15\text{ }^\circ\text{C}15 ∘C.
- Increasing the temperature increases the ‾\underline{\quad\quad\quad\quad} energy of the molecules.
- This results in more frequent ‾\underline{\quad\quad\quad\quad} between the catalase enzymes and the ‾\underline{\quad\quad\quad\quad} molecules.
The students want to find the precise temperature at which the catalase enzymes denature and completely stop functioning. Suggest two ways they can extend or modify their experiment to find this out.