Calculate the activation energy for vacancy formation in aluminum, given the equ
ID: 484592 • Letter: C
Question
Calculate the activation energy for vacancy formation in aluminum, given the equilibrium number of vacancies at 773 K is 7.57 x 10 ^23 m^-3. The atomic weight and density at 773 K for aluminum are, respectively, 26.98 g/mol and 2.62 g/cm^3. Calculate the activation energy for vacancy formation in aluminum, given the equilibrium number of vacancies at 773 K is 7.57 x 10 ^23 m^-3. The atomic weight and density at 773 K for aluminum are, respectively, 26.98 g/mol and 2.62 g/cm^3. Calculate the activation energy for vacancy formation in aluminum, given the equilibrium number of vacancies at 773 K is 7.57 x 10 ^23 m^-3. The atomic weight and density at 773 K for aluminum are, respectively, 26.98 g/mol and 2.62 g/cm^3.Explanation / Answer
Calculate the activation energy for vacancy formation in aluminum, given the equilibrium number of vacancies at 773 K is 7.57 x 10 ^23 m^-3.
The atomic weight and density at 773 K for aluminum are, respectively, 26.98 g/mol and 2.62 g/cm^3.
N = N A PAl / AAl
=(6.022 x10^23 atoms/mol)(2.62 g / cm^3) / 26.98 g /mol
= 5.85 × 10^22 atoms/cm^3 = 5.85 × 10^28 atoms/m^3
Qv = - ln KT Ln(Nv /N )
Qv = - ln KT Ln(Nv /N )
= - (8.62 x10^-5 eV/atom- K)(773 K) ln[7.57x 10^23 / 5.85 x 10^28 ]
= = 0.75 eV/atom-----------answer