What is the total number of tetrahedral voids in 0.6 mole of compound that forms hcp structure?

Calculate the number of unit cells in 0.4 g metal if the product of density and volume of unit cell is $1.2 \times 10^{-22} \mathrm{~g}$.

What is the total number of particles present in base centred unit cell?

Calculate the number of unit cells in 0.9 g metal if it forms bec structure. $\left[\rho \times \mathrm{a}^3=3 \times 10^{-22}\right.$ gram$]$