NEET Chemistry The Solid State Questions Solved

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An element occurs in bcc structure. It has a cell edge length of 250 pm. Calculate the molar mass if its density is 8.0 g cm-3. Also calculate the radius of an atom of this element.

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Concept Questions :-

Density/Formula/packing fraction/ Semiconductors

Given : For bcc structure, Z = 2

Edge of the unit cell, a = 250 ρm

Density of the element, ρ = 8.0 g/cm3

M = ?      r = ?

Using the formula

ρ = Z×Ma3×N0 M = ρ×a3×N0Z

M =(8.0g cm-3)×(250×10-10cm)3×(6.022×1023)atoms2

M = 752750000×10-72  M = 37.6 g mol-1

For, bcc, a = 4r3     250 = 4r3

  r = 250×1.734 = 108.25 pm

Difficulty Level:

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