Question

Metallic rhodium crystallizes in a face-centred cubic lattice with a unit-cell edge length of $3.803\stackrel{\circ }{A}$. Calculate the molar volume of rhodium including the empty spaces.

Answer 1

Volume of unit cell $=(3.803\times {10}^{-8}cm{)}^3=55.0\times {10}^{-24}ions$

Also no. of atoms of $Rh$ present in unit cell $=4$

$\therefore$ Volume/ atom of $Rh=\frac{55.0\times {10}^{-24}c{m}^3}{4}=13.75\times {10}^{24}$

$\therefore$ Volume of Avogadro no. of $Rh=13.75\times {10}^{-24}6.023\times {10}^{23}=8.282c{m}^3$.