Collision Theory + Surface Area

Question 1

What is the activation energy?

Answer 1

The minimum energy which the reactants need to react.

Question 2

In what two ways can you increase the rate of reaction?

Answer 2

• Increase the frequency of reacting particles colliding with each other.
• Increase the energy they have when they collide.

Question 3

What ways can the rate of a reaction be increased?

Answer 3

• Increase the temperature.
• Increase the concentration of the reactants.
• Increase the pressure of reacting gases.
• Increase the surface area of solids.
• Use a catalyst.

Question 4

Explain why breaking larger pieces of a soild into smaller pieces increases the rate of reaction.

Answer 4

• More exposed surfaces meaning higher surface area.
• More collisions in the same amount of time.
• The finer the powder, the faster the reaction.

Question 5

Why does increasing temperature increase the rate of reaction?

Answer 5

The particles collide more often as they have more energy.

Question 6

Why does increasing concentration increase the rate of reaction?

Answer 6

There are more particles of the reactants in the same volume, so they are more ‘crowded together’. So, they are more likely to collide.

Question 7

Why does increasing pressure increase the rate of reaction?

Answer 7

The gas particles are squashed more closely together. So, they are more likely to collide.

Question 8

Why does having a catalyst increase the rate of reaction?

Answer 8

• A catalyst provides an alternate reaction pathway.
• This has a lower activation energy.
• A higher portion of the reactant particles have sufficient energy to react.
• The frequency of collisions increases.