11- Rates Of Reaction

Question 1

What are factors that affect rate of reaction?

Answer 1

1. The surface area or size of solid particles
2. The concentration of solutions
3. The temperature
4. The presence of a catalyst

Question 2

How does temperature effect rate of reaction?

Answer 2

1. The particles are moving faster, so there are more frequent collisions
2. The particles also have more energy, so more of the particles have the activation energy and react when they collide.
3. Hence there are more successful collisions between particles in a given time (the successful collisions are more frequent)
4. And so the rate of reaction is faster.

Question 3

How does the concentration affect the rate of reaction?

Answer 3

1. There are more particles present in the same volume
2. And so there are more successful collisions (with the activation energy) between particles in a given time (the successful collisions are more frequent)
3. And so the rate of reaction is faster.

Question 4

How does the surface area of solid reactants affect the rate of reaction?

Answer 4

1. There are more particles on the surface exposed to the other reactant
2. And so there are more successful collisions (with the activation energy) between particles in a given time (the successful collisions are more frequent)
3. And so the rate of reaction is faster.

Question 5

What is gas pressure?

Answer 5

The force that the gas exerts on the walls of its container

Question 6

Increasing pressure increases the rate of reaction because…

Answer 6

There are more particles in a smaller volume more frequent collisions.

Question 7

How do you work out the rate of reaction?

Answer 7

Rate of reaction= 1/time

Question 8

What is a catalyst?

Answer 8

A catalyst is a substance that increases the rate of a reaction without being used up.

Question 9

What is the catalyst for the decomposition of hydrogen peroxide to make oxygen?

Answer 9

Manganese(IV) oxide

Question 10

What is the catalyst used in the reaction of nitrogen and hydrogen in the Haber process to make ammonia.

Answer 10

Iron

Question 11

How does the presence of a catalyst affect the rate of reaction?

Answer 11

1. Providing an alternative reaction pathway of lower activation energy.
2. And so there are more successful collisions (with the activation energy) between particles in a given time (the successful collisions are more frequent).
3. And so the rate of reaction is faster.

Question 12

What is activation energy?

Answer 12

Activation energy is the minimum energy needed for a reaction to occur.

Question 13

What is rate of reaction?

Answer 13

The rate of reaction is a measure of the speed at which reactants are changed into products.

Question 14

What is collision theory?

Answer 14

Collision theory states that for a reaction to occur the reacting particles must collide together with enough energy to react.