What is Activation Energy?
Activation energy refers to the amount of energy required by certain chemicals for them to have a reaction. Some chemicals are able to react with each other immediately if placed in close proximity. But there are other chemical types that need some extra push to gain some sort of activity between them. This extra push needed for chemical reaction is called activation energy.
Like in the case of sodium and water, no activation energy is needed for them to react with each other. Other chemicals also behave in this way and there are others that need some external factor to start a particular reaction. When reactions occur between chemicals, molecular bonds may also break. But breaking molecular bonds in certain chemicals does not simply require simple mixing of the chemicals. Some require precise placement and orientation for a chemical reaction to occur. This is where activation energy enters the process. An “energy barrier” has to be reached to start the reaction process, and sometimes this is not possible by simple collision between molecules. An external force must be applied to start chemical activity and this may be in the form of heat or addition of some enzyme.
When a chemical reaction finally starts, it will result into some energy release allowing for the chemical activity to continue and sometimes lead to another reaction. And if this cycle goes on, this is now called a chemical chain reaction. An example of this chemical activity can be demonstrated on forest fires. In forest fires, a spark may start the burning of wood. Once the wood catches fire, the heat generated will make the fire bigger and may consume the entire tree. As the fire gets bigger and bigger, other trees will get burned too.
It is said that having an energy barrier or activation energy requirement for various chemical reactions actually make for a stable environment. If no such barrier exists, chemicals around us will react with each other much more easily which may not have a good result.