1. Ch. 18 Reaction Rates

2. 2 Types of Reactions
Endothermic: Energy is absorbed into the system.

3. Exothermic: Energy is released by the system.

4. Examples of Exothermic: Anything that gives off heat
Running your car             Charging your cell phone
Exercising                        Lighting a bunsen burner
Rubbing your hands together
Examples of Endothermic: Anything that absorbs heat
Sweating (evaporation)             Melting ice cubes
Cooking an egg                           Baking a cake

5. What causes reactions to speed up?
Adding energy to the system will increase the frequency of collisions between molecules, leading to more reactions occurring. 
What causes reactions to speed up?

6. Catalysts
Provide an alternate pathway for the reaction which results in a lower activation energy.