The molar mass of nitric acid (HNO3) is 63.012 g/mol.
Case matters: CO is carbon monoxide, Co is
cobalt. Brackets and hydrates are fine — try
or
.
| Element | Atoms | Atomic mass | Mass contributed | Percent |
|---|---|---|---|---|
| Hydrogen (H) | 1 | 1.0080 | 1.008 | 1.60% |
| Nitrogen (N) | 1 | 14.007 | 14.007 | 22.23% |
| Oxygen (O) | 3 | 15.999 | 47.997 | 76.17% |
| Total | 5 | 63.012 | 100.00% |
1.008 + 14.007 + 47.997 = 63.012 g/mol
Grams and moles
25 g of nitric acid is 0.3967 mol, because 25 ÷ 63.012 = 0.3967.
These elements have no single atomic weight. Their isotopic mix varies slightly depending on where on Earth the sample came from, so the figure used here is the conventional value IUPAC publishes for when one number is needed: hydrogen is 1.0080, and really lies between 1.00784 and 1.00811; nitrogen is 14.007, and really lies between 14.00643 and 14.00728; oxygen is 15.999, and really lies between 15.99903 and 15.99977.
Nitric acid is 63.012 g/mol, of which oxygen makes up 76.17%, nitrogen 22.23% and the acidic hydrogen a bare 1.60%.
The concentrated laboratory grade runs at about 68%, and at a density of 1.41 g/mL that works out to roughly 15 moles per litre. Fuming nitric acid goes higher still and carries dissolved nitrogen dioxide, which is what gives old bottles their yellow tint: the acid slowly decomposes in light, and the colour is a decomposition product rather than an impurity from manufacture.
It is monoprotic, so one mole neutralises one mole of base. But nitric acid is also a strong oxidising agent, and that second role does not appear anywhere in the molar mass. Reacting it with copper does not produce hydrogen gas the way a non-oxidising acid would; it produces nitrogen oxides instead, and the stoichiometry depends on concentration.
Together with sulfuric acid it forms the nitrating mixture behind explosives and dyes.