The minimum amount of energy that particles must collide with to react
Endothermic Reaction
Takes in energy from the surrounding causing the temperature of the surroundings to decrease. Energy needed to break existing bonds is greater than the energy released from forming new bonds
Exothermic Reaction
Transfers energy to surroundings so the temperature of the surroundings increases. Energy released from the forming of new bonds is greater than energy needed to break existing bonds
Overall Energy Change
The difference between the sum of the energy needed to break the bonds in the reactants and the sum of energy released when products are formed
