Answer: The value of Avogadro's number is [tex]6.07\times 10^{23}[/tex]
Explanation:
NaCl crystallizes as face centered cubic, where Z = 4
To calculate the density of metal, we use the equation:
[tex]\rho=\frac{Z\times M}{N_{A}\times a^{3}}[/tex]
where,
[tex]\rho[/tex] = density of KCl = [tex]1.984g/cm^3[/tex]
Z = number of atom in unit cell = 4 (FCC)
M = atomic mass of KCl = 74.55 g/mol
[tex]N_{A}[/tex] = Avogadro's number = ?
a = edge length of unit cell = [tex]628pm=628\times 10^{-10}cm[/tex] (Conversion factor: [tex]1cm=10^{10}pm[/tex] )
Putting values in above equation, we get:
[tex]1.984=\frac{4\times 74.55}{N_A\times (628\times 10^{-10})^3}\\\\N_A=6.07\times 10^{23}[/tex]
Hence, the value of Avogadro's number is [tex]6.07\times 10^{23}[/tex]
