Ammonia is 317\tfrac{3}{17}173​ hydrogen by mass, i.e., about 17.6% of the weight of ammonia is due to hydrogen atoms.

Quick Scoop

  • The chemical formula for ammonia is NH 3_33​, meaning 1 nitrogen atom and 3 hydrogen atoms per molecule.
  • The approximate atomic masses are: nitrogen ≈ 14 and hydrogen ≈ 1 (in atomic mass units).
  • Total mass of NH3_33​ ≈ 14+3×1=1714+3\times 1=1714+3×1=17 units, and hydrogen contributes 3×1=33\times 1=33×1=3 of those units.
  • So, the fraction of ammonia’s mass that is hydrogen is 3/173/173/17, which is about 0.176, or 17.6%. Multiple chemistry help sources frame this answer as 3/173/173/17 in fraction form.

In other words, if you put a sample of ammonia on a balance, a bit less than one‑fifth of that reading comes from the hydrogen in the molecule.

TL;DR: When you weigh ammonia, the mass fraction that is hydrogen is 3/173/173/17 (≈17.6%). Information gathered from public forums or data available on the internet and portrayed here.