# Tag Info

The density of iron is also the density of the unit cell : $\pu{7.874 g|cm3}$. Multiply this density by the volume of the unit cell. It gives you the mass of this unit cell : $\pu{7.874 g/cm3 · 2.314 · 10^{-23} cm3 = 1.861 · 10^{-22}} g$ . This is exactly twice the mass of an iron atom, as $1$ atom weighs : $\pu{\frac{56 ~g/mol}{6·10^{23} atom/mol}}$ = \$\pu{...