Balancing atoms in the decomposition reaction Steps:

• NH₄NO₃ has 2 N, 4 H, 3 O atoms per formula unit.
• All H atoms form H₂O, so 4 H require 2 H₂O, using 2 O atoms and leaving 2 N + 1 O.
• The gas must contain exactly 2 N and 1 O to balance without extra products.
• N₂O matches this (formula N₂O), yielding NH₄NO₃ → N₂O + 2 H₂O.

Why C is correct:

• This equation produces one gas (N₂O) and water, matching the problem's products.

Why the others are wrong:

• A. NO: Provides 1 N and 1 O per molecule; cannot balance 2 N and excess O without another product.
• B. NO₂: Provides 1 N and 2 O per molecule; overproduces O and underproduces N.
• D. N₂: Provides 2 N but no O; leaves 3 O unaccounted for in water alone.

Final answer: C