the edge length of fcc unit cell is 400pm.if molar mass is 60.22g/mol.then find the density for na=6.022×1023
Answer (1)
27th Jul, 2020
Hi
According to the question For an FCC crystal, atoms are in touch along the diagonal of the unit .
4r= 2
a, where a is that the edge length of unit and r is that the radius of atom.
Substituting values within the above expression, we get
r= 42 ×407
=143.9 pm
Number of atoms per unit cell (FCC) =4
Mass of 1 unit cell =197×4=788amu=1.66×10 −27 ×788kg=1.30808×10 −24 kg
Volume of 1 unit cell =(407×10 −12 ) 3 m 3 =6.741×10 −29 m 3 =2.824×10 −28 m 3
Density= 6.741×10 −29
1.30808×10 −24
=19404.83kg/m 3 =19.4g/cm 3
Hope helpful.
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