NEET Chemistry The Solid State Questions Solved

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An element X crystallizes in f.c.c structure. 208 g of it has 4.2832×1024 atoms. Calculate the edge of the unit cell, if density of X is 7.2 g cm-3.

Z = 4(fcc)      d = 7.2 g/cm3       a=?

4.2832×1024 atoms have mass = 208 g

6.022×1023 atoms have mass

=  2084.2832×1024× 6.022 × 1023 = 29.24 (at. mass)

a3Z×Md×NA = 4×29.247.2×6.022×1023

    =269.6 ×10-24 cm3

 a = 6.46 × 10-8 cm = 6.46 A

Difficulty Level:

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