What are the solutions for Question 3, including the investigative question, reasons for effective collisions, the function of a catalyst, and its effect on particle distribution?

3.1 Write down the investigative question for this investigation.
The investigation varies the temperature of the hydrogen peroxide solution while keeping its concentration and the amount of catalyst constant. The aim is to study how this factor affects the reaction rate.
The investigative question is:
How does the temperature affect the rate of decomposition of hydrogen peroxide?

3.2 The Maxwell-Boltzmann distribution curves, X and Y, for particles in both experiments 1 and 2.

3.2.1 Write down a reason why the molecules at the RIGHT of line L undergo effective collisions.
The molecules to the right of line L possess kinetic energy that is equal to or greater than the activation energy. This is the minimum energy required for collisions to be effective and lead to a reaction.

3.2.2 What is the function of Copper (II) oxide in this reaction?
Copper (II) oxide acts as a catalyst in this reaction.

3.2.3 How does the presence of copper (II) oxide in this reaction affect the number of particles to the LEFT of line L? Choose from DECREASES, INCREASES or REMAINS THE SAME.
The presence of copper (II) oxide (a catalyst) lowers the activation energy of the reaction. However, a catalyst does not change the kinetic energy distribution of the reactant particles. Therefore, the number of particles with kinetic energy less than the original activation energy (represented by line L) REMAINS THE SAME.

Final Answer:

3.1: $\boxed{\text{How does the temperature affect the rate of decomposition of hydrogen peroxide?}}$
3.2.1: $\boxed{\text{They have kinetic energy equal to or greater than the activation energy.}}$
3.2.2: $\boxed{\text{It acts as a catalyst.}}$
3.2.3: $\boxed{\text{REMAINS THE SAME}}$