Question

State the definition of the partial molar Gibbs energy.

Answer 1

Explanation :

As we know that the Gibbs free energy is not only function of temperature and pressure but also amount of each substance in the system.

`G=G(T,P,n_1,n_2)`

where,

`n_1\text{ and }n_2` is the amount of component 1 and 2 in the system.

Partial molar Gibbs free energy : The partial derivative of Gibbs free energy with respect to amount of component (i) of a mixture when other variable
`(T,P,n_j)` are kept constant are known as partial molar Gibbs free energy of
`i^(th)` component.

For a substance in a mixture, the chemical potential
`(\mu)` is defined as the partial molar Gibbs free energy.

The expression will be:

`\bar{G_i}=\mu_i=(\partial G)/(\partial n_i)_((T,P,n_j))`

where,

T = temperature

P = pressure

`n_i\text{ and }n_j` is the amount of component 'i' and 'j' in the system.