Chemical Reactions 3 - Rate of Reaction

Question 1

What is rate of reaction?

Answer 1

Rate of reaction refers to the change in amount of reactants/products over time (mass or volume). A reaction is either fast or slow.

Question 2

What are the factors affecting rate of reaction?

Answer 2

1. Concentration
2. Temperature
3. Surface Area (Solids)
4. Pressure of Gases
5. Presence of catalyst

Question 3

What is a catalyst?

Answer 3

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

Question 4

What is concentration?

Answer 4

Concentration refers to the amount of solids/solute per unit volume.

Question 5

What does collision theory state?

Answer 5

Collision theory states:
1. Products are only formed when reactant molecules collide with each other in a proper orientation
2. Reactant Particles/Molecules need a minimum amount of energy to form the product. This energy is known as activation energy

Question 6

What is activation energy?

Answer 6

Activation energy refers to the minimum amount of energy required to form a product.

Question 7

Explain how the increase in concentration affects rate of reaction.

Answer 7

When concentration is increased, more particles are present and hence more particles collide with each other resulting in more products, hence the rate of reaction is higher.

Question 8

Explain how the increase in temperature affects rate of reaction.

Answer 8

When temperature is increased, there is a higher kinetic energy of the particles and hence more frequent collisions were occur, thus increasing the rate of reaction.

Question 9

Explain how the increase in surface area affects rate of reaction.

Answer 9

When surface area is increased, greater surface is exposed for collision to happen, hence there will be more product and a higher rate of reaction.

Question 10

Explain how the increase in pressure affects rate of reaction.

Answer 10

When pressure is increased, there is less space between particles and hence concentration increases. Thus, more collisions occur resulting in a higher rate of reaction.

Question 11

Explain how the addition of a catalyst affects rate of reaction.

Answer 11

When a catalyst is added, the reaction pathway changes and activation energy decreases and therefore the rate of reaction increases.

The increase in concentration of catalyst results in the increase in the rate of reaction.