Aplique ley de la conservacion de la masa en
Na2O + (NH4)2SO4 + H2O + NH3

Explanation:

To apply the law of conservation of mass, we must understand the meaning  and basis of this law.

The law of conservation of mass is applied to balance chemical equations. Based on this law, we know that the amount of reactants and products must be the same.

To balance this reaction;

        Na₂O   +   (NH₄)₂SO₄  →   Na₂SO₄  +  NH₃ + H₂O

let us use a simple mathematical approach to solve this;

          aNa₂O   +   b(NH₄)₂SO₄  →   cNa₂SO₄  +  dNH₃ + eH₂O

a, b, c, d and e are numbers that will balance the equation;

Conserving Na;    2a   = 2c

                    O:      a + 4b = 4c + e

                    H:      8b  = 3d + 2e

                    N:       2b  = d

                    S:         b  = c

assume that c  = 1;

                     a  = 1

                     b  = 1

                     d  = 2

                     e  = 1

          Na₂O   +   (NH₄)₂SO₄  →   Na₂SO₄  +  2NH₃ + H₂O