# NEET Chemistry The Solid State Questions Solved

Silver crystallizes in a face centred cubic system, 0.408 nm along each edge. The density of silver is 10.6 $g/c{m}^{3}$ and the atomic mass is 107.9 g/mol. Calculate Avogadro's number.

(1) $6.00×{10}^{23}$ atom/mol

(2) $9.31×{10}^{23}$ atom/mol

(3) $6.23×{10}^{23}$ atom/mol

(4) $9.61×{10}^{23}$atom/mol

(1) The unit cell has a volume of (0.408 $×{10}^{-9}m{\right)}^{3}=6.79×{10}^{-29}{m}^{3}$ per unit cell and contains four atoms. The volume of 1 mole of silver is,

$107.9\text{\hspace{0.17em}}g/mol\left[\frac{{\left(1×{10}^{-2}m\right)}^{3}}{10.6g}\right]=1.02×{10}^{-5}{m}^{3}/mol$; where 107.9 g/mol is the molecular mass of the silver

The number of unit cells per mol. is,

unit cells per mol.

and the number of atoms per mol. is, atom/mol.

Difficulty Level:

• 58%
• 9%
• 33%
• 2%
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