1. IIIIIIIVV Reaction Rates

2. Collision Theory n Reaction rate depends on the collisions between reacting particles. n Successful collisions occur if the particles... 1. collide with each other 2. have the correct orientation 3. have enough kinetic energy to break bonds

3. Collision Theory n Particle Orientation Required Orientation Successful Collision Unsuccessful Collisions

4. Collision Theory n Activation Energy (E a )  minimum energy required for a reaction to occur Activation Energy

5. Collision Theory n Activation Energy  depends on reactants  low E a = fast rxn rate EaEa

6. Exothermic Reaction

7. Endothermic Reactions

8. Factors Affecting Rxn Rate n Surface Area  high SA = fast rxn rate  more opportunities for collisions  Increase surface area by… - using smaller particles - dissolving in water

9. Factors Affecting Rxn Rate n Concentration  high conc = fast rxn rate  more opportunities for collisions

10. Factors Affecting Rxn Rate n Temperature  high temp = fast rxn rate  high KE - fast-moving particles - more likely to reach activation energy

11. Factors Affecting Rxn Rate n Temperature Analogy: 2-car collision 5 mph “fender bender” 50 mph “high-speed crash”

12. Factors Affecting Rxn Rate n Catalyst  substance that increases rxn rate without being consumed in the rxn  lowers the activation energy

13. Factors Affecting Rxn Rate n Enzyme Catalysis