1. Reaction Kinetics
Chapter 17

2. Collision Theory
In order for reactions to occur between substances, their particles must collide
Collision theory: the set of assumptions regarding collisions and reactions
There are three possible outcomes for collisions with only one resulting in a reaction

3. Three Outcomes
Only the first one results in a reaction

4. Reasons why a reaction will not occur
The collision is not energetic enough to supply the required energy
The colliding molecules are not oriented in a way that enables them to react with each other

5. Activation Energy
Activation energy: the minimum energy required to transform the reactants into an activated complex
Activated complex: a transitional structure that results from an effective collision and that persists while old bonds are breaking and new bonds are forming

7. Reaction Rate
Reaction rate: the change in concentration of reactants per unit time as a reaction proceeds
The rate of reaction depends on the collision frequency and the collision efficiency

8. Factors that Influence Reaction Rate
Anything that increases the collision rate increases the rate of the reaction
Concentration/pressure
Surface area
Temperature
Presence of a catalyst
Stirring or agitation

9. Concentration/Pressure
Increase the concentration of the reactants and more collisions will occur
Increasing the pressure for reacting gases is like increasing the concentration

10. Surface Area
Especially important in a reaction that involves substances in phases that do not mix, like a solid with a liquid, or a gas with a liquid
An increase in the surface area in contact will increase the collision rate

12. Temperature Increasing the temperature causes more collisions
more importantly, it increases the proportion of molecules with enough energy to overcome the activation energy
The average energy of the particles is proportional to the temperature in Kelvins

13. Catalyst
Catalyst: a substance which, when present in relatively small amounts, increases the rate of a chemical reaction, but which is not consumed during the reaction
A catalyst provides a new reaction pathway with a lower activation energy
This means that a greater number of collisions will have the required energy to react

15. Stirring or Agitation
Stirring or agitation allows more collisions to take place, higher reaction rate