How does the collision theory explain how chemical reactions occur?
The collision theory states that molecules must collide in order for reactions to occur.
When molecules of the reactant hit each other, only a certain percentage of the collisions cause a chemical change.
If the molecules are moving too slowly, they will bounce off each other. There will be no reaction.
If the molecules are moving rapidly but do not collide with the correct orientation, they will again bounce off each other. There will be no reaction.
Successful collisions must have the correct orientation and enough "activation" energy to break the existing bonds and form new ones. This results in the formation of products.
At any given moment, only a small percentage of molecules has both the correct orientation and enough activation energy for a reaction to occur. Otherwise, most reactions would occur almost immediately.