Question

The density of chromium metal is 7.20 g/cm3. if the unit cell is cubic

Answer 1

Given, Density, β=7.20g/cm^3    Since, simple cubic unit cell, therefore no. of atoms in the unit cell, Z=1, atomic mass of chromium, m=52g, Avogadro's no. N=6.022x10^23.

We know, β=mZ/Na^3, where a is the edge length of the unit cell.

=>a^3=mZ/Nβ

=>a^3=52x1/6.022x10^23x7.2

=>a^3=1.12x10^-23

=>a=2.23x10^-8 cm

=>a=2.23 pm

Therefore edge length of the unit cell is 2.23 pm.

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