NEET Chemistry The Solid State Questions Solved

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An element crystallizes in a b.c.c. lattice with cell edge of 500pm. The density of the element is 7.5g cm-3. How many atoms are present in 300 g of the element?    (3)

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Concept Questions :-

Density/Formula/packing fraction/ Semiconductors

z=2

d=z×Ma3×N

N=z×M/d×a3

N=2×300g/7.5gcm-35×10-83

N=6.4×1023atoms

OR 

d=z×Ma3×N

7.5=2×M5003×10-30×6.022×10-23

M=7.5×125×10-24×6.022×10232

=282.3g/mol

282.3 g= 6.022×1023atoms

300 g =6.022282.3×1023×300

         =6.4×1023atoms

Difficulty Level:

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