# How can the mass of an atom from the periodic table be represented in respect to moles?

Dec 21, 2016

Well, the atomic mass is always quoted in units of $g \cdot m o {l}^{-} 1$.

#### Explanation:

The mass quoted on the Periodic Table for iron is $55.85 \cdot g \cdot m o {l}^{-} 1$.

That is $\text{Avogadro's Number}$ of iron atoms, i.e. $6.022 \times {10}^{23}$ individual iron atoms, has a mass of $55.85 \cdot g$.

When we wish to work out the molar quantity, the molar equivalence of a given mass of iron, say $5.0 \cdot g$, we take the quotient:

$\text{Moles of iron}$ $=$ (5.00*cancelg)/(55.85*cancelg*mol^-1)=??*1/(mol^-1)=??mol.

And thus the quoted molar quantity represents a specific number of inidvidual iron atoms, or, alternatively, formula units......