1. COLLISION THEORY

2. HOW REACTIONS HAPPEN Rate of reaction – How quickly a reaction happens. 1.Energy of the collision: Reactant must have enough energy to react. a.This is known as the activation energy 2.Geometry of collision: Particles must be oriented in the proper way for a reaction to occur

3. FACTORS EFFECTING REACTION RATE Temperature: Higher temperature increases the rate of reaction Higher temp Higher kinetic energy More high energy collisions Faster reaction In general, reactions will occur most rapidly if the reactants are a liquid or a gas

4. FACTORS EFFECTING REACTION RATE Concentration: High concentration increases the rate of reaction More particles More collisions Faster reaction

5. FACTORS EFFECTING REACTION RATE Surface area/particle size: Small particles increase the surface area of a solid and increases the rate of reaction (heterogeneous reactions) More particle exposed More collisions Faster reaction

6. FACTORS EFFECTING REACTION RATE Pressure: Increasing the pressure of a gas will increase the rate of reaction More particles in close proximity to each other More collisions Faster reaction

7. CATALYSTS AND ENZYMES A catalyst speeds up a reaction without being consumed in the reaction. Enzymes – A large molecule, usually a protein, that catalyze biological reactions Enzymes and catalysts provide alternative pathways for a reaction to occur Lowers the activation energy More collision will have enough energy to react

8. PRACTICE Page 604 #1-#4 Page 628 #8