Question

An fcc lattice has a lattice parameter $a$ equal to $400$ pm. Calculate the molar volume (in mL) of the lattice including all the empty space.

• A. $10.8$
• B. $96.2$
• C. $8.6$
• D. $9.6$

Answer 1

The correct option is D $9.6$

Volume $=a^3=(400\times {10}^{-12}m{)}^3=64\times {10}^{-24}c{m}^3$

$V_{total}=V{N}_A=64\times {10}^{-24}\times 6.02\times {10}^{23}\approx 38.4$

Molar volume $=\frac{1}{4}{V}_{total}=\frac{1}{4}\times 38.4=9.6$ mL