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