Calculate the number of unit cells in 10.8 g metal $\left(\varrho a^3=7.2 \times 10^{-22} \mathrm{~g}\right)$
Calculate the number of unit cells in 10.8 g metal $\left(\varrho a^3=7.2 \times 10^{-22} \mathrm{~g}\right)$
$1.5 \times 10^{22}$
$3.0 \times 10^{22}$
$4.5 \times 10^{22}$
$6.0 \times 10^{22}$
Solution
No. of unit cells in $x \mathrm{~g}$ of metal $=\frac{\mathrm{x}}{\rho \times \mathrm{a}^3}=\frac{10.8 \mathrm{~g}}{7.2 \times 10^{-22} \mathrm{~g}}=1.5 \times 10^{22}$ unit cells