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.


Given, edge length (a) = 3.61 × 10 -8 cm

Given lattice is fcc, therefore, no. of atoms per unit cell (z) = 4


We know, atomic mass f copper = 63.5 g/mol


Avogadro number, N A = 6.022 × 1023 g/mol


To prove, density (d) = 8.92 g cm-3


We know that, density





d = 8.9657 cm-1


Hence, the calculated density = the density of copper = = 8.9657 cm-1


15
1