Complete Question
The complete question is shown on the first uploaded image
Answer:
The density is
Explanation:
From the question we are told that
The lattice constant is 
Generally the volume of the unit cell is 
=> ![V = [0.387 *10^{-9}]^2](https://tex.z-dn.net/?f=V%20%20%3D%20%20%5B0.387%20%2A10%5E%7B-9%7D%5D%5E2)

Converting to
We have 
The molar mass of Tungsten is constant with a value 
One mole of Tungsten contains
unit cells
Where
is a constant for the number of atom in one mole of a substance(Tungsten) which is known as Avogadro's constant
Now for FCC distance the number of atom per unit cell is n = 4
Mass of Tungsten (M) = 
=> Mass of Tungsten (M) =
=> Mass of Tungsten (M) =
Now
The density of Tungsten is

substituting values

