(P2)Rates Of Reaction And Energy Changes

Question 1

What must happen to particles in order for a reaction to happen?

Answer 1

Reactant particles must collide with each other and the collisions must have enough energy

Question 2

What is the activation energy?

Answer 2

The minimum amount of energy needed by reactant particles for a reaction to happen

Question 3

Why does the rate of reaction increase when the concentration of the dissolved reactants increase?

Answer 3

There are more particles in the same volume, so the frequency of successful collisions increase

Question 4

When lumps are broken up into a powder, why does the rate of reaction increase?

Answer 4

Increases the surface area, more particles of the reactant are made available, frequency of successful collisions increases

Question 5

What happens in exothermic reactions?

What happens in endothermic reactions?

Answer 5

Heat is given out to the surroundings, so the reaction mixture or surroundings increase in temperature.
Heat is taken in from the surroundings, so the reaction mixture or surroundings decrease in temperature.

Question 6

Is breaking bonds endothermic/exothermic?

What about making bonds?

Answer 6

Breaking bonds = endothermic as energy is needed

Making bonds = exothermic as energy is released