X-ray diffraction studies show that copper crystallises in an fcc unit cell with cell edge of `3.608 xx 10^(-8) ` cm . In a separate experiment , copper is determined to have a density of 8.92 g/`cm^(3)` , calculate the atomic mass of copper .

Explanation

In case of fcc lattice , number of atomic per unit cell z = 4 atoms
Therefore ,M = `(dN_(A) a^(3))/(z)`
`= (8.92 g cm^(-3) xx 6.022 xx 10^(23) "atoms" mol^(-1) xx (3.608 xx 10^(-8) cm)^(3))/(4 "atoms") = 63.1 ` g/mol .
Atomic mass of copper = 63.1 u