Calculate the number of unit cells in 0.4 g metal if the product of density and volume of unit cell is $1.2…
Calculate the number of unit cells in 0.4 g metal if the product of density and volume of unit cell is $1.2 \times 10^{-22} \mathrm{~g}$.
$1.1 \times 10^{21}$
$2.2 \times 10^{21}$
$3.3 \times 10^{21}$
$4.4 \times 10^{21}$
Solution
No. of unit cell in $x \mathrm{~g}$ of metal
$\begin{aligned}
=\frac{\mathrm{x}}{\rho \mathrm{a}^3} & =\frac{0.4 \mathrm{~g}}{1.2 \times 10^{-22} \mathrm{~g}} \\
& =3.3 \times 10^{21}
\end{aligned}$