why is energy absorbed in both endothermic and exothermic reactions?

Question

both endothermic and exothermic reactions absorb some energy to start with

Answer 1

Exothermic reactions also need energy to start. All reactions are a collision of atoms or molecules. This collision sticks together to form an "activated complex". The old bonds break, the new bonds are formed and then the products appear.

But for the activated complex to be created requires energy. This extra enery is called the activation energy of a reaction. All of this extra energy is given back when the reaction is concluded, but it must be there to start to the reaction or nothing happens.

A good example of an exothermic reaction would be burning a fuel, such as methane gas or gasoline. The combustion is a reaction with oxygen in the air. But without a spark (activation energy) nothing happens.

Answer 2

theyre not! exothermic=energy is RELEASED!!

heres how i remember it: exo, exit, released....ya kno (word association)

(ENDOTHERMIC, absorbs energy)