Mole ratios how can the coefficients in a chemical equation be interpreted

The coefficient in a balanced chemical equation  indicates the mole ratio of both reactants and products.  

Explanation:

For example lets consider the reation between Hydrogen and Oxygen to form water:

2H2 + O2 2H2O

In this reaction, the coefficients of the balanced reaction can be transformed to Mole ratio according to Avogadro's Law which states that at standard temperature and pressure, equal volume of gases contain the same  number of moles.

So the mole ratio for the above equation is  the  ratio of the coefficient:

2moles     :     1 mole               :          2 moles

the reaction mixture contains some ammonia, plus a lot of unreacted nitrogen and hydrogen. the mixture is cooled and compressed, causing the ammonia gas to condense into a liquid. the liquefied ammonia is separated and removed. the unreacted nitrogen and hydrogen are then recycled back into the reactor .