Molar mass of an element is `Mg*mol^(-1)`. The element crystallises in a cubic structure with face-centred unit cells. What will be the number of unit cells in x g of the element?

Explanation

The number of atoms present in xg of the element = `x/MxxN` (N = Avogadro's number)
In face-centred cubic unit cell, number of atoms present per unit cell = 4.
Hence, 4 atoms`-=`1unit cell
`thereforex/MxxN" atoms"-=(xN)/(4M)" unit cells"`
Therefore in xg of the element, the number of unit cells will be `(xN)/(4M)`.