Molar MassMolar mass of calcium chloride (CaCl2)
The molar mass of calcium chloride, CaCl2, is 110.98 g/mol. One mole of it, which is 6.022 × 1023 formula units, has a mass of 110.98 grams.
About calcium chloride
Calcium chloride is a white salt that takes up water strongly from the air. The anhydrous solid is used as a drying agent in the laboratory and for melting ice on roads in cold countries.
The working
The formula CaCl2 has 1 calcium atom and 2 chlorine atoms, 3 atoms in all. Multiply each count by the atomic weight of the element and add:
| Element | Atoms | Atomic weight | Total | Share by mass |
|---|---|---|---|---|
| Calcium (Ca) | 1 | 40.078 | 40.078 | 36.11% |
| Chlorine (Cl) | 2 | 35.45 | 70.900 | 63.89% |
40.078 + 2 × 35.45 = 110.978 g/mol
With the rounded atomic masses used in many school books (Ca = 40, Cl = 35.5) the answer is 111 g/mol. The difference from 110.98 is too small to matter in most school sums.
Percentage composition
By mass, CaCl2 is 36.11% calcium and 63.89% chlorine. The largest share comes from chlorine. In a 100 g sample there are 36.1 g of calcium and 63.9 g of chlorine.
Worked examples
Grams to moles. How many moles are in 5 g of CaCl2? Divide the mass by the molar mass: 5 ÷ 110.98 = 0.04505 mol.
Moles to grams. What is the mass of 0.25 mol of CaCl2? Multiply: 0.25 × 110.98 = 27.74 g.
Counting particles. 5 g contains 0.04505 mol × 6.022 × 1023 = 2.713 × 1022 formula units.
Making a solution. A 0.1 mol/L solution contains 0.1 × 110.98 = 11.1 g of CaCl2 in each litre. For 250 mL, weigh 2.774 g and make it up to the mark with water.
Quick conversion tables
| Amount | Mass |
|---|---|
| 0.1 mol | 11.1 g |
| 0.5 mol | 55.49 g |
| 1 mol | 111 g |
| 2 mol | 222 g |
| 5 mol | 554.9 g |
| Mass | Moles |
|---|---|
| 1 g | 0.009011 mol |
| 10 g | 0.09011 mol |
| 100 g | 0.9011 mol |
| 1 kg | 9.011 mol |
For other amounts use the grams and moles converter.
Questions people ask
What is the molar mass of CaCl2?
The molar mass of calcium chloride (CaCl2) is 110.98 g/mol, or 110.978 g/mol before rounding, using IUPAC abridged atomic weights.
How many moles are in 100 g of CaCl2?
100 ÷ 110.98 = 0.9011 mol.
What is the mass of one formula unit of CaCl2?
Divide the molar mass by the Avogadro constant: 110.98 ÷ 6.022 × 1023 = 1.843 × 10-22 g.
What is the percentage of chlorine in CaCl2?
Chlorine makes up 63.89% of the mass of CaCl2: 2 × 35.45 ÷ 110.978 × 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.