Rates of reactions

Question 1

Activated energy

Answer 1

The minimum energy required to start a chemical reaction

Question 2

Activated complex

Answer 2

A high energy, unstable, temporary transition state between the reactants and
the products.

Question 3

Catalyst

Answer 3

A substance that increases the rate of a chemical reaction but remains unchanged at the
end of the reaction.

Question 4

The reaction rate of a chemical reaction

Answer 4

The change in concentration per unit time of either a

reactant or product.

Question 5

Heat of reaction

Answer 5

– The net change in chemical potential energy of the system. ΔH > 0 for
endothermic reactions and ΔH < 0 for exothermic reactions.

Question 6

Exothermic reaction

Answer 6

Reactions which transform chemical potential energy into thermal energy.

Question 7

Endothermic reaction

Answer 7

Reactions which transform thermal energy into chemical potential energy.

Question 8

Explain collision theory

Answer 8

collision theory is a model that explains that
a reaction will only proceed when reactant particles collide effectively. An effective (or successful) collision is one in which the colliding reactant particles have:
the correct orientation sufficient energy, i.e. kinetic energy equal to or greater than the activation energy

Question 9

Factors that effect the reaction rate of a substance

Answer 9

Nature of substance
Surface area of substance
Temperature
Pressure
Concentration
Catalyst