Rates of Reaction

Question 1

What happens to the rate of reaction if the concentration of dissolved reactant increases or if the pressure of a reacting gas increases?

Answer 1

The rate of reaction increases, this is because more particles of reactant are available so the frequency of successful collisions increases

Question 2

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

Answer 2

The rate of reaction increases because more particles of reactant are available meaning the frequency of successful collisions increases

Question 3

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

Answer 3

The rate of reaction increases because the particles gain energy so they move faster and the frequency of successful collisions increases

Question 4

In exothermic reactions is heat given out or taken in?

Answer 4

Given out, the reaction mixture or the surroundings increase in temperature

Question 5

In endothermic reactions is heat energy taken in or given out?

Answer 5

Taken in, the reaction mixture or surroundings decrease in temperature

Question 6

Why are some reactions exothermic?

Answer 6

Because more heat energy is released when making bonds in the products than is required to break bonds in the reactants

Question 7

Why are some reactions endothermic?

Answer 7

Because less heat energy is released making bonds in the products than is required to break bonds in the reactants

Question 8

How do you calculate the energy change of a reaction?

Answer 8

Total energy in - total energy out, if the answer is negative the reaction is exothermic, if the answer is positive the reaction is endothermic