# How many moles of iron are in 1.2*10^25 atoms of iron?

Sep 13, 2016

There are approx. $6.022 \times {10}^{23}$ iron atoms per mole of ion. This quantity, this number of iron atoms has a mass of $55.85 \cdot g$. And of course, when we quote the mass of iron we say $55.85 \cdot g \cdot m o {l}^{-} 1$.
$\left(1.2 \times {10}^{25} \cdot \text{atoms of iron")/(6.022xx10^23*"iron atoms per mole}\right)$ $\cong$ $20 \cdot \text{moles}$