Gold (atomic mass 197 u, atomic radius = 0.144 m ) crystallizes in a face centred unit cell. Determine the density of gold

Gold (atomic mass 197 u, atomic radius = 0.144 m ) crystallizes in a f

1.	Gold (atomic mass 197 u, atomic radius = 0.144 m ) crystallizes in a face centred unit cell. Determine the density of gold
Answer» Solution :For fcc unit cell , `r=a/(2sqrt2)` or `a=2sqrt2 r=2xx1.414 XX 0.144`NM = 0.407 nm =`0.407xx10^(-7)` CM `rho=(ZxxM)/(a^3xxN_0)=(4xx197 "g MOL"^(-1))/((0.407xx10^(-7)cm)^3 xx (6.02xx10^23 mol^(-1)))=19.4 g cm^(-3)`