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Question

Chemistry Question on packing efficiency

The fraction of total volume occupied by the atoms present in a simple cube is

A

π6\frac{\pi}{6}

B

π32\frac{\pi}{3\sqrt{2}}

C

π42\frac{\pi}{4\sqrt{2}}

D

π4\frac{\pi}{4}

Answer

π6\frac{\pi}{6}

Explanation

Solution

The correct answer is A) π6\frac{\pi}{6}

For simple cube, Radius(r)=a2\, \, \, \, \, \, \, \, \, Radius(r)=\frac{a}{2}\, \, \, \, \, \, \, \, \, \, \, \, \,[a = edge length)

The volume of the atom =43π(a2)3\frac{4}{3}\pi \Bigg(\frac{a}{2}\Bigg)^3 Packing fraction=Z×14πr3a3=\frac{Z\times\frac{1}{4}\pi r^3}{a^3}

The volume of the sphere (atoms) in a unit cell. For simple cubic, Z = 1 atom Packing fraction =43π(a2)3a3=π6=\frac{\frac{4}{3}\pi\Bigg(\frac{a}{2}\Bigg)^3}{a^3}=\frac{\pi}{6}

Read more from chapter:**cube **