Question

solve the following numerical tagged :

Answer 1

Silver forms  FCC lattice.  In face centered cubic lattice structure, there are 8 atoms in the 8 corners of a cube.  There are  6 atoms in the center of 6 faces.

So effectively  8 corner atoms contribute 8 * 1/8 = 1 atom.  The 6 other atoms contribute 6 * 1/2 = 3 atoms.

There are 4 atoms in one cube.  The side of the cube is : 4.07 * 10⁻⁸ cm

   Density of crystal = 10.5 gm / cm³

So volume of 1 cube in lattice = 4.07³ * 10⁻²⁴ cm³
Mass of one cube of lattice = 10.5 * 4.07³ * 10⁻²⁴  gm = 707.90 * 10⁻²⁴ gm

There are 4 atoms in one cube.
Mass of one atom  = 1.76975 * 10⁻²⁴ gm

Mass of one mole of Silver atoms : 1.76975 * 10⁻²⁴ * 6.023 * 10²³  gms
               = 106.5922  gms /mole    OR,  106.5922 u    or   amu
 
in the above, We multiplied with the Avogadro number..