Answer:
Na = 5.911 × [tex]10^{21}[/tex] atoms/cm³
Explanation:
given data
silver-gold alloy C Au = 17 wt%
densities ρ Au = 19.32 g/cm³
densities ρ Ag = 10.49 g/cm³
atomic weights A Au = 196.97 g/mol
atomic weights A Ag = 107.87 g/mol
solution
we will apply here formula for number of gold atoms that is
Na = [tex]\frac{NA * C Au}{\frac{C Au * A Au}{\rho Au} + \frac{A Au * (100-C Au)}{\rho Ag}}[/tex] ............................1
here NA is Avogadro's number and ρ is density of two element and A is atomic weight
put here value
Na = [tex]\frac{6.022*10^{23} * 0.17}{\frac{0.17 * 196.97}{19.32} + \frac{196.97 * (100-0.17)}{10.49}}[/tex]
Na = 5.911 × [tex]10^{21}[/tex] atoms/cm³