Molar MassMolar mass of silver chloride (AgCl)
The molar mass of silver chloride, AgCl, is 143.32 g/mol. One mole of it, which is 6.022 × 1023 formula units, has a mass of 143.32 grams.
About silver chloride
Silver chloride is the curdy white precipitate formed when silver nitrate meets a chloride. It darkens in sunlight. Weighing it is a classic way to find the amount of chloride in a sample.
The working
The formula AgCl has 1 silver atom and 1 chlorine atom, 2 atoms in all. Multiply each count by the atomic weight of the element and add:
| Element | Atoms | Atomic weight | Total | Share by mass |
|---|---|---|---|---|
| Silver (Ag) | 1 | 107.87 | 107.870 | 75.27% |
| Chlorine (Cl) | 1 | 35.45 | 35.450 | 24.73% |
107.87 + 35.45 = 143.320 g/mol
With the rounded atomic masses used in many school books (Ag = 108, Cl = 35.5) the answer is 143.5 g/mol. The difference from 143.32 is too small to matter in most school sums.
Percentage composition
By mass, AgCl is 75.27% silver and 24.73% chlorine. The largest share comes from silver. In a 100 g sample there are 75.3 g of silver and 24.7 g of chlorine.
Worked examples
Grams to moles. How many moles are in 40 g of AgCl? Divide the mass by the molar mass: 40 ÷ 143.32 = 0.2791 mol.
Moles to grams. What is the mass of 3 mol of AgCl? Multiply: 3 × 143.32 = 430 g.
Counting particles. 40 g contains 0.2791 mol × 6.022 × 1023 = 1.681 × 1023 formula units.
Quick conversion tables
| Amount | Mass |
|---|---|
| 0.1 mol | 14.33 g |
| 0.5 mol | 71.66 g |
| 1 mol | 143.3 g |
| 2 mol | 286.6 g |
| 5 mol | 716.6 g |
| Mass | Moles |
|---|---|
| 1 g | 0.006977 mol |
| 10 g | 0.06977 mol |
| 100 g | 0.6977 mol |
| 1 kg | 6.977 mol |
For other amounts use the grams and moles converter.
Questions people ask
What is the molar mass of AgCl?
The molar mass of silver chloride (AgCl) is 143.32 g/mol, or 143.320 g/mol before rounding, using IUPAC abridged atomic weights.
How many moles are in 100 g of AgCl?
100 ÷ 143.32 = 0.6977 mol.
What is the mass of one formula unit of AgCl?
Divide the molar mass by the Avogadro constant: 143.32 ÷ 6.022 × 1023 = 2.380 × 10-22 g.
What is the percentage of silver in AgCl?
Silver makes up 75.27% of the mass of AgCl: 1 × 107.87 ÷ 143.320 × 100.
Which values? This site uses the abridged standard atomic weights published by IUPAC (CIAAW), read on 12 November 2026. Your textbook or question paper may round them differently, for example H = 1 and O = 16, so its answer can differ slightly. In an exam, use the values the paper gives.