Q15 Copper crystallises into a fcc lattice with edge length 3.61 × 10–8 cm. Show that the calculated density is in agreement with its measured value of 8.92 g cm–3.

Q15 Copper crystallises into a fcc lattice with edge length 3.61 × 10^–8 cm. Show that the calculated density is in agreement with its measured value of 8.92 g cm^–3.

Solution :–

Given that

Length of edge, a = 3.61x10–8 cm

Atomic mass of cupper, M = 63.55 g/mol

Avogadro constant, NA  = 6.022x1023 per mol

Number of atoms in unit cell of FCC, Z= 4

Use formula of density 

Plug the values in this formula we get