Rates Of Reaction

Question 1

What is a rate if reaction?

Answer 1

Change in concentration of reactant or product over period of time

Question 2

How can you calculate rate of reaction?

Answer 2

Draw tangent & calculate gradient
Change in concentration / time

Question 3

What is activation energy?

Answer 3

Minimum energy required for reaction to take place

Question 4

What happens to the rate of reaction when the concentration increases?

Answer 4

Increases:
- more reactant particles in a given volume
- more frequent collisions
- if solution isn’t in excess, the graph will be steeper & finish at a higher point

Question 5

What happens to the rate of reaction when the pressure increases?

Answer 5

Increases
- same no. of particles but in a smaller volume
- more frequent collisions

Question 6

What happens to the rate of reaction when the surface area increases?

Answer 6

Increases
- increase number of exposed particles
- more frequent collisions
- graph is steeper, but it finishes at the same point
Larger surface area = smaller pieces

Question 7

What happens to the rate of reaction when the temperature increases?

Answer 7

Increases
- particles have more energy so move faster
- more frequent collisions
- more particles have energy greater than the activation energy
- more frequent successful collisions
- graph is steeper, but finishes at same point

Question 8

What is a catalyst?

Answer 8

Increases the rate of reaction without being changed themselves
- it lowers the activation energy by providing an alternative pathways
- the graph is steeper, but finishes at the same point