The diffusivity of ni in mgo is 1.23 x 10-16 m2/s at 1200˚c and 1.45 x 10-14 m2/s at 1800˚c. calculate the activation energy and the pre-exponential constant

Answer : The Activation energy, Ea = 201.820 KJ/mol

                The Pre-exponential constant, = 1.7658 ×

Solution :  Given,

Diffusivity of Ni at , = 1.23 ×  

Diffusivity of Ni at , = 1.45 ×  

Temperature,   = = 1200 + 273 = 1473 K

Temperature,   = = 1800 + 273 = 2073 K

Value of R = 8.314 J/mol/K

Formula used :

     ..........(1)

This formula convert into logarithm term for the calculation of activation energy. So the formula is,

 ........(2)

Now put all the values in above formula (2), we get

Rearranging the terms, we get the value of Activation energy, (Ea) as

Ea = 201.820 KJ/mol

Now, we have to calculate the value of Pre-exponential constant, bye using formula (1)

now put all the values in formula,we get

Rearranging the terms, we get the value of Pre-exponential constant, as

= 1.7658 ×