Why are decomposition reactions called the opposite of combination reactions ? Write equations for these reactions.

Explanation

In the decomposition reaction, a compound is broken down into simple compounds or elements. Eg :
`CuCO_(3)(s) overset("heat") to CuO(s)+CO_(2)(g)`
Combination reaction is a reaction in which two are more elements or compound combine to form a new compound e.g
`N_(2)(g)+3H_(2)g to 2NH_(3)(g)`