What are exothermic and endothermic reactions?
Exothermic Reaction: The reaction in which heat (energy) is evolved is called Exothermic Reaction.
Endothermic Reaction: The reaction in which heat (energy) is absorbed from its environment is called Endothermic Reaction.
Buring of carbon is a type of exothermic reaction and combination of nitrogen and oxygen to give nitric oxide is a type of endothermic reaction.