Question

An fcc lattice has lattice parameter $a=400$ pm. Calculate the molar volume of the lattice including all the empty space.

• A. 10.8 mL
• B. 96 mL
• C. 8.6 mL
• D. 9.6 mL

Answer 1

The correct option is D 9.6 mL

Volume of unit cell $={400}^3=64\times {10}^{-24}$ $c{m}^3$

Volume of $N_A$ unit cell $=64\times 6\times {10}^{23}\times {10}^{-24}$ $c{m}^3=\frac{384}{10}=38.4$ $c{m}^3$

Molar volume $=\frac{38.4}{4}=9.6$ $mL$