Calculate the number of unit cell in $0.5$ g metal if the product of volume and density of unit cell is $6.65 \times 10^{-23}$ g

What is the total number of adjacent unit cells shared by each face particle of fcc unit cell ?

A metal forms fcc structure. Calculate the volume of fcc unit cell in $\text{cm}^3$ if void volume is $1.66 \times 10^{-23}\ \text{cm}^3$.

Calculate the mole fraction of solute in solution if vapour pressure of a solution and pure solvent are 27 mm Hg and 30 mm Hg respectively at 298 K.