Rates Of Reactions

Question 1

Activation energy

Answer 1

The minimum energy required to start a chemical reaction OR The energy required to form the activated complex.

Question 2

Activated complex

Answer 2

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

Question 3

A 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 (ΔH)

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 reactions

Answer 6

Reactions which transform chemical potential energy into thermal energy.

Question 7

Endothermic reactions

Answer 7

Reactions which transform thermal energy into chemical potential energy.