Barium crystallizes in a body-centered cubic system with atoms at all lattice points and an edge length of 5.02 angstroms. Calculate its density in g/cm3.

Answer : The density is,

Explanation :

Formula used :  

.............(1)

where,

= density  = ?

Z = number of atom in unit cell (for BCC = 2)

M = atomic mass  of barium = 137.3 g/mole

= Avogadro's number =  

a = edge length of unit cell  =

Conversion used :

Now put all the values in above formula (1), we get

Thus, the density is,

the answer to your question is c