Chemistry - Solid State Question with Solution | TestHub

The formula for the density of a unit cell is given by $d=\frac{Z\times M}{a^3\times N_A}$

For a body-centered cubic (bcc) structure, the number of atoms per unit cell is $Z=2$.

Given:
$d=8.6{\text{ g cm}}^{-3}$
$a^3\times N_A=22.0{\text{ cm}}^3{\text{ mol}}^{-1}$

Substituting the values into the formula:
$8.6=\frac{2\times M}{22.0}$

$M=\frac{8.6\times 22.0}{2}$

$M=8.6\times 11.0=94.6{\text{ g mol}}^{-1}$

Answer: $94.6\mathrm{g}{\mathrm{mol}}^{-1}$