Question

3.9 The accompanying graph shows the self-diffusion coefficient for Na+ in an NaCl crystal doped with CdCl. NaCl is believed to form Schottky defects. Using the data in the graph, calculate the following. (a) The activation energy for self-diffusion of Na+ in NaCl. (b) The enthalpy of formation of Schottky defects in NaCl (in eV). 10-8 TIT 3 x 10-96 10-94 → 10-10 - - - - 3 x 10-11 Diffusion coefficient (cm2/s) 10-11 10-12 5x 10-13 11.23 10-13LLLLLL 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1/T 103 1.7

Answer 1

Solo Given data, The accompanying graph shows the Self-diffusion Coefficient for wat in an Nacl coystal doped with Cada. Nach is beived to from Schottky defects. 10 3х10 x 10 coefficie Diffusion -1.23 10 o 1.2 163 114 15 16 17 TX103

an The activation Energy for self-diffusion of Nat in Nach Da = D. Exp Cream DAB at 4+ (1x10²) is = 3x10 cm?/sec DAB at ₃ (1.23 x10²) is = 3x10 cm? / sec. . - 3x10 / Sec m ( 9 ) Chko? - 1.360) - (to) (to a3 15°) 72.34a.com (40.33 <10%) 4.6 = Ca (0.23 x103) 20000 - co [ Ea - 166280] Ea = 166280 ]

b) The Enthalpy of formation of Schottky defects in Nac. DA E akt RA DH. Qkq - 2x1-38 x 10" X 166280 R 8.314 5.52x1olej 1.681019 J = lev AH = 5.5a xio'9 1.6x1079 AH = 3.45 ev