Collision theory posits that for a reaction to occur, particles must collide with sufficient kinetic energy and the correct orientation to form an activated complex. The activation energy barrier needs to be surpassed for reactants to convert into products, with factors such as temperature, concentration, and surface area affecting collision efficacy. A catalyst can lower the activation energy, thus increasing the reaction rate without altering the energy barrier itself.

1. COLLISION THEORY:
States that atoms, ions, and molecules
must collide
in order to react.

2. •According to collision theory, particles will react to form
products if they collide with enough kinetic energy.
•Particles that do not have enough energy to react bounce
apart unchanged when they collide (no reaction).
Collision Theory:

3. When two reactant particles collide, they may
form an activated complex.
• An activated complex (transition state) is an unstable
arrangement of atoms that forms for a moment at
the peak of the activation-energy barrier.
• The activated complex forms only if the colliding
particles have enough energy and correct
orientation.

4. 4
Activated
Complex
Activation Energy
barrier
(minimum
amount
of energy
required)
Enough energy ?

5. An effective collision of oxygen and hydrogen
molecules produces water molecules.
2 H2 + O2
Activated Complex
2 H2O

6. An ineffective collision of oxygen and
hydrogen molecules produces no reaction;
the reactants bounce apart unchanged.
2 H2 + O2
Activated Complex
2 H2 + O2

7. The Activation-energy barrier must be crossed before
reactants are converted into products:
Exothermic Reaction Endothermic Reaction

8. PARTICLES MUST COLLIDE WITH:
(EFFECTIVE COLLISION)
•Favorable (correct) orientation to form the activated
complex (transition state).
•Sufficient energy to form the activated complex, and
overcome the Activation Energy, Ea (minimum
amount of energy required for a reaction to occur)

9. Energy
Reaction progress
(Endothermic
reaction)
Activated
Complex
∆H Energy absorbed by
reaction
Products
Reactants
Ea
Activation
Energy

10. Collision Theory
products no products
1. Favourable Geometry
A successful collision requires:
Poor Geometry

11. Describe and Graph the Relationship between the Following
Ea and the rate
Ea
Rate
Decreasing the Ea increases the rate- inverse.

12. Describe and Graph the Relationship between the Following
Temperature and the rate
Temp
Rate
Increasing the temperature increases the rate- direct.

13. Describe and Graph the Relationship between the Following
Concentration and the rate
Conc
Rate
Increasing the concentration increases the rate- direct.

14. Describe and Graph the Relationship between the Following
Ea and the temperature
Ea
Temp
No relationship!
The only way to change the Ea is by adding a catalyst!

15. Which factors increase the percentage of successful collisions?
I. Increasing temperature
II. Increasing concentration
III. Increasing surface area
IV. Adding a catalyst