3Anelement has a body centred cubic (bec) structure with a celledge of 288 pm. The dthe element is 7.2 g/cm3. How many atoms are present in 208 g of the element ?Ans-24.18 *10 atom]

3Anelement has a body centred cubic (bec) structure with a celledge of

1.	3Anelement has a body centred cubic (bec) structure with a celledge of 288 pm. The dthe element is 7.2 g/cm3. How many atoms are present in 208 g of the element ?Ans-24.18 *10 atom]
Answer» Formula units per unit cell Z = 2 for BCCcubic unit cell lattice parameter a = 288 pm = 288 x10-8cmVolume V = a3=2.39X10^-23cm3Density d = 7.2g/cm3NA = Avogadro constant = 6.022x10²³Molecular mass M =?We know thatDensity d = ZM/NA X a3M = dxNA x a3/ZOn Substituting valuesM= 7.2g/cm3x(6.022x10²³)X (6.022x10²³)/2= 51.8gmol-151.8 g of element contains 6.022X10^23208g of this element contains=?= 6.022X10^23X208/51.8=2.42X10^24atoms.