Collision theory ( chemistry)

The collision theory states that for a chemical reaction to occur, the reacting particles must:

• collide with each other
  
• possess activation energy
  
  

Activation energy is the minimum energy required by the reacting particles in order for reaction occur. The figure below shows the energy profile diagram for exothermic and endothermic reaction.

Exothermic Reaction:

Endothermic reaction:

The collision that are succesful in producing a chemical reaction are called effective collisions.

Collision theory is used to explain the factors that affect the rates of reactions. Any factor that increases the frequency of effective collision will increase the rate of reaction.

Factor affecting the rate of reaction:

• Size of particle: dcrease in particle size will increase the total surface area exposed to collision.
• Concentration: increase in concentration increases the number of perticles per unit volume. So will give more chance to effective collision occur.
• Temperature: increase in temperature increase the number of paticles possesing activation energy.
• Catalyst: will lowers the activation energy.