Factors affecting rates of reaction

Question 1

What is the activation energy?

Answer 1

The minimum amount of energy the reactants need to collide with each other and react.

Question 2

What is the collision theory?

Answer 2

For particles to react, they must collide with each other with sufficient energy.

Question 3

What are the factors that affect rates of reaction?

Answer 3

Temperature
Surface area
Concentration of a solution/Pressure of gas
Presence of a catalyst

Question 4

How does increasing the temperature increase the rate of reaction?

Answer 4

1) Increased temperature means particles move faster.

2) If particles move faster, they will collide more frequently.

3) This means more collisions will have enough energy to make the reaction happen.

Question 5

How does increasing the concentration or pressure increase the rate of reaction?

Answer 5

When the concentration or pressure is increased, there will be more particles and therefore more frequent collisions.

Question 6

How does increasing the surface area increase the rate of reaction?

Answer 6

1) Breaking a reactant into smaller pieces will increase its surface area : volume ratio.

2) This means particles around it will have more area to work on so there will be more frequent collisions.

Question 7

How does using a catalyst increase the rate of reaction?

Answer 7

1) They decrease the activation energy needed for a reaction to occur.

2) They provide an alternative reaction pathway with a lower activation energy.

Question 8

What are some everyday catalysts?

Answer 8

Nickel - used in the production of margarine
Iron - used in the production of ammonia
Platinum - used in the catalytic converters of car exhausts