1. Controlling Reactions
Factors that affect Reaction Rates

2. Rate of a Reaction: The speed at which a chemical reaction proceeds
The rate at which a chemical reaction takes place depends on the way the particles of the reactants interact.
Chemical reactions do not all occur at the same rate. A particular reaction can be manipulated by changing different factors.

3. 1. Activation Energy: the minimum amount of energy needed to start a chemical reaction
All chemical reactions require a certain amount of activation energy to get started.
This is the Energy that is needed to break the bonds in the reactants.

4. 2. Catalysts: increase the reaction rate by lowering the required Activation Energy
Catalysts are not changed by the chemical reaction
Example: Manganese Dioxide
(it was present on both sides of the equation)
Biological Catalysts are called Enzymes
Inhibitors slow down Reactions (ex. preservatives in food)

5. 3. Concentration: the amount of a substance in a given volume
Increasing the concentration of reactants supplies the reaction with more particles to react
Example: Ice Tea Mix
If you add one teaspoon of ice tea mix to your glass it
does not taste strong. The more teaspoons you add, the
more flavor you taste

6. 4. Surface Area: a measure of the total area that the surface of an object occupies
When a solid substance reacts
with a liquid or a gas, only the
particles on the surface of the
solid come into contact with
the liquid or gas.

7. 5. Temperature: a measure of the average energy, the random motion, of particles in matter
As energy is added to matter in the form of heat, the particles start to move faster and spread out.
Faster moving particles will have more energy

8. Answer these Questions:
What is Activation Energy? And why does each reaction need Activation Energy?
How does the addition of a Catalyst speed up the reaction rate of that particular reaction?
How does the concentration of reactants affect the rate of a chemical reaction?