1. CHEMICAL KINETICS

2. Chemical Kinetics
Study of the speed
of reactions

3. (or reactants disappear)
Reaction Rate
Rate at which
products appear
(or reactants disappear)

4. Reactions are usually several steps (not just one step)
All of the steps together
is called the reaction mechanism.

6. Rate-Determining Step
The slowest step of the reaction mechanism (determines the overall reaction rate)

7. Molecules must collide in order to react
Collision Theory
Molecules must collide in order to react

8. In order for the collision to work, it must have the proper orientation and enough energy.

9. ENERGY DIAGRAMS

10. Reaction that releases heat
Exothermic Rxn
Reaction that releases heat
(heat exits)

11. Reaction that absorbs heat
Endothermic Rxn
Reaction that absorbs heat
(heat goes en)

12. Amount of energy needed to start a reaction
Activation Energy
Amount of energy needed to start a reaction

13. Amount of heat lost or gained in a reaction (unit = kJ)
Enthalpy Change (DH)
Amount of heat lost
or gained in a
reaction
(unit = kJ)

14. Reactions with a HIGH Ea proceed at a SLOW rate.

15. Substance that speeds up a reaction by lowering the Ea
Catalyst
Substance that speeds up a reaction by lowering the Ea

16. Four factors that affect reaction rate:
Temperature
Concentration
Surface Area
Catalyst