Q13 of 26 Page 1

An element crystallizes in a fcc lattice with cell edge of 400 pm. Calculate the density if 200 g of this element contain 2.5 × 1024 atoms.

Given,


Edge length, a = 400 pm = 400 m


Z = 4 (fcc lattice)


6.022 1023 atoms are present in 1 mole of element.


2.5 × 1024 atoms are present in 200 g of element.


6.022 1023 atoms are present in g/mol.


Therefore, M = 48.16 g/mol


Substituting values in d =


d=


d = 4.99 106 g/m3


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