Answer:
Add two coefficient in front of water molecules.
Explanation:
Chemical equation;
NH₄NO₃ → N₂O + H₂O
Balanced chemical equation;
NH₄NO₃ → N₂O + 2H₂O
The given reaction is balanced.
There are two nitrogen, four hydrogen and three oxygen atoms are on both side of equation.
This equation correctly follow the law of conservation of mass.
Coefficient with reactant and product.
Reactant Product
NH₄NO₃ = 1 N₂O = 1
H₂O = 2
