Question

How many moles of tetrahedral voids present in the $2$ cm long iron cube, assuming cubic shape, is FCC unit cell with density of iron equal to $7.0$ g cm${}^{-3}$? (Atomic mass of Fe is $56$ amu)

• A. $2$
• B. $4$
• C. $6$
• D. $8$

Answer 1

The correct option is A $2$

As we know,
Mass of cube $=V\times d=8\times 7.0$ g

Moles of atom $=\frac{8\times 7.0}{56}=1.0$

Also, as we know

Moles of tetrahedral void $=$ twice of number of atoms $=2\times 1.0=2$