Question

X-ray diffraction studies show that of copper crystallizes in an fcc unit cell with cell edge of `3.608xx10^(-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 .

Answer 1

`rho=(ZxxM)/(a^3xxN_0)` or `M=(rhoxxa^3xxN_0)/Z`
For fcc lattice, Z=4
Hence, `M=((8.92 g cm^(-3))(3.608xx10^(-8) cm)^3 (6.022xx10^23 "atom mol"^(-1)))/"4 atoms"=63.1 g mol^(-1)`
`therefore` Atomic mass of copper =`63.1 g mol^(-1)`