The molar mass of silver nitrate (AgNO3) is 169.872 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 |
|---|---|---|---|---|
| Silver (Ag) | 1 | 107.8682 | 107.868 | 63.50% |
| Nitrogen (N) | 1 | 14.007 | 14.007 | 8.25% |
| Oxygen (O) | 3 | 15.999 | 47.997 | 28.25% |
| Total | 5 | 169.872 | 100.00% |
107.868 + 14.007 + 47.997 = 169.872 g/mol
Grams and moles
25 g of silver nitrate is 0.1472 mol, because 25 ÷ 169.872 = 0.1472.
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: 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.
Silver nitrate is 169.872 g/mol, and silver alone accounts for 63.50% of that. The compound is expensive for exactly that reason: almost two thirds of what you weigh out is a precious metal.
It is the standard reagent for testing halides. Add it to a solution containing chloride and silver chloride drops out as a white precipitate; bromide gives cream, iodide gives yellow. The test works because those three silver salts are almost insoluble while silver nitrate itself dissolves readily.
Gravimetric chloride analysis depends on the molar masses lining up. Precipitate the chloride as silver chloride at 143.318 g/mol, dry it, weigh it, and multiply by the ratio of chlorine to the whole compound to recover how much chloride was present. Before instrumental methods, this was how chloride was measured.
Silver nitrate stains skin black on contact with light, which is the same photochemistry that made silver halides the basis of photographic film.