Chemistry - Solid State Question with Solution | TestHub

$\therefore$Mass of one unit cell$=\text{V}\times \text{d}$(V is volume, d is density)

$={\text{a}}^3\times \text{d}$

Also, density$=\frac{\text{z}\times \text{at. wt.}}{{\text{a}}^3\times \text{av. no.}}$

$\therefore$Mass of one unit cell$=\frac{{\text{a}}^3\times \text{z}\times \text{at. wt.}}{{\text{a}}^3\times \text{av. no.}}$

$=\frac{\text{z}\times \text{at. wt.}}{\text{av. no.}}$

$=\frac{4\times 58\text{.}5}{6\text{.}02\times 10^{23}}$(z = 4 for cubic shape)

$=38\text{.}87\times 10^{-23}\text{g}$

$\therefore$No. of unit cell in 1 g$=\frac{1}{38\text{.}87\times 10^{-23}}$

$=2\text{.}57\times 10^{21}$