Answer:
[tex]\large \boxed{\text{55.8 u}}[/tex]
Explanation:
1. Calculate the volume of the unit cell
V = l³ = (2.866 × 10⁻⁸ cm)³ = 2.354 × 10⁻²³ cm³
2. Calculate the mass of a unit cell
[tex]\text{Mass} = 2.866 \times 10^{-23}\text{ cm}^{3} \times \dfrac{\text{7.87 g}}{\text{1 cm}^{3}} = 1.853 \times 10^{-22} \text{ g}[/tex]
3. Calculate the mass of one atom
A body-centred unit cell contains two atoms.
[tex]\text{Mass of 1 atom} = \dfrac{1.853 \times 10^{-22} \text{ g}}{\text{2 atoms}} \times \dfrac{\text{1 u}}{1.661 \times 10^{-24}\text{ g}} = \textbf{55.8 u}\\\\\text{The molar mass of Fe from the Periodic Table is $\large \boxed{\textbf{55.845 g/mol}}$}[/tex]
