Molar Mass of Ammonia

M(\mathrm{NH_3}) = 0.017031\ \text{kg/mol}

Value	0.017031 kg/mol
Status	Measured: ± 0.0000012 kg/mol (0.00007 relative)
Source	IUPAC
Categories	Chemistry molar-mass

M(NH₃) in every molar mass unit

gram per mole	17.031 g/mol
kilogram per mole	0.017031 kg/mol

Learning zone

Ammonia at 17.031 g/mol contains 14.007 g/mol of nitrogen, so the ratio 17.031/14.007 = 1.216 converts between the two ways every laboratory reports it. A permit written as 5 mg/L "as N" is 6.08 mg/L "as NH₃"; confusing the two is one of the most common and most expensive unit errors in wastewater compliance.

Ammonia is also a refrigerant, R-717, and a lighter-than-air gas at 0.73 g/L, which is why a leak in an industrial plant room rises rather than pooling. In water it forms a weak base with pK_b 4.75, so the split between toxic free NH₃ and comparatively harmless NH₄⁺ swings sharply with pH — at pH 7 barely 0.6 % of total ammonia is the free form, at pH 9 it is 36 %, which is exactly why a fish kill can follow an otherwise harmless pH excursion.

Used by these solvers

Moles from Mass (n = m/M)

n = \frac{m}{M}

Molarity (C = n/V)

C = \frac{n}{V}

Henderson–Hasselbalch Equation (Weak Acid Buffer)

\mathrm{pH} = \mathrm{p}K_a + \log_{10}\!\frac{[\mathrm{A^-}]}{[\mathrm{HA}]}