# The molar mass of calcium chloride (CaCl2) represents the mass of one mole of what?

Sep 5, 2016

Represents the mass of one mole of calcium chloride, which is $110.98 \cdot g$.

#### Explanation:

The molar mass is the mass of $\text{Avogadro's number}$ of particles, where $\text{Avogadro's number } = 6.022 \times {10}^{23} \cdot m o {l}^{-} 1$, and is abbreviated as ${N}_{A}$.

Thus in one mole of calcium we have ${N}_{A}$ calcium atoms (well calcium ions, but these are really equivalent!) and $2 \times {N}_{A}$ chlorine atoms.

Why do we use ${N}_{A}$ and the mole concept?

Well it enables us to equate the macro world of grams and kilograms, what we measure on a balance, with the submicro world of atoms and molecules, of which we can conceive, but cannot observe directly. The concept of molar equivalence is central to the study of chemistry. If you know the formula, and you know the mass of the stuff, use of ${N}_{A}$ allows you to measure very precisely the number of atoms and molecules in a process.