Question

Calculate the value of D at 713°C for the diffusion of some species in a metal for which the values of D0 and Qd are 1.6 × 10-6 m2/s and 188 kJ/mol, respectively.

Answer 1

`1.75*10^(-16)m^2/s`

Step-by-step explanation:

Data given

Maximum diffusion coefficient,
`D_(o)=1.6*10^(-6)m^(2)/s\\`

Activation Energy,
`E_(a)=188kJ/mol=188000J/mol`

Temperature,T=713+273=986K

Universal gas constant, R=8.314J/mk

Since diffusion is the movement of particles from a higher concentration to a lower concentration, the coefficient of diffusion is expressed as

`D=D_(0)e^{-E_(A)/RT}`

If we substittute valies we arrive at

`D=D_(0)e^{-E_(A)/RT}\\D=1.6*10^(-6)e^(-188000/(8.314*986))\\D=1.75*10^(-16)m^2/s`