NEET Chemistry The Solid State Questions Solved

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An element crystallizes in a structure having fcc unit cell of an edge 200 pm. Calculate the density if 200 g of this element contains 24×1023 atoms.

24×1023 atoms of an element have mass = 200 g

 6.022×1023 atoms of an element have mass =

20024×1023 × 6.022 ×1023 = 50.18 g

Given : a = 200 ρm = 200×10-12 cm,

Z = 4(For fcc), M = 50.18 g

Using the formula : ρ = Z×Ma3×NA

 ρ = 4×50.18(200×10-10)3×6.022×1023

 ρ = 200.728×6.022×10-1 = 2007.248.176 = 41.66 g/cm3

Difficulty Level:

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