According to the law of conservation of mass, the total mass of the products is equal to that of reactants, in a chemical reaction.
\(\text3{H}_2 (g) + \text{N}_2 (g) → \text2{NH}_3(g)\)
6 g 28 g X g
The mass of \(NH_3\) produced is equal to the sum of the masses of hydrogen and nitrogen that reacted to give \(NH_3\).
Hence, the mass of \(NH_3\) = X g = 28 + 6 = 34 g.