In the balanced chemical equation for the formation of ammonia. n2 + h2 > nh3 the total sum of all the coefficients is

Balancing of the chemical reaction involves keeping the number of atoms of a certain element equal in both sides of the equation. For this item, the balanced chemical equation would be,

      N2 + 3H2 --> 2NH3

The numerical coefficients are therefore 1 for N2, 3 for H2, and 2 for NH3. The sum of the numerical coefficients is 6.

6

The mass has escaped into a gas which you can not see so the law stays true.