Resumen

MAYORGA, M.  y  DOMINGUEZ, B.. An Application of the Concept of Non-Equilibrium Chemical Potential to Describe Transport Properties of Solutions. Rev. Soc. Quím. Méx [online]. 2000, vol.44, n.1, pp.67-73. ISSN 0583-7693.

We explain how the concept of thermodynamic internal degrees of freedom (TIDF) is used to extend the concept of chemical potential when some irreversible processes are present. Particularly, we choose the velocities of Brownian interacting particles as TIDF and after using the Gibbs entropy postulate and the postulates of non-equilibrium thermodynamics, we obtain the Fokker-Planck (FP) equations for the Brownian particles under a temperature gradient, which we use to obtain the corresponding momentum and energy balance equations. We analyze the diffusion regime where we obtain a novel expression for the thermal difffusion coefficient. In addition, applying a dimensional analysis to the internal energy balance equation, we find a temperature dependence of the heat conducting time that leads to conclude that the heat conduction is faster in a solution composed of suspended particles in a solvent compared with a simple liquid.

Palabras llave : Nonequilibrium Thermodynamics; Thermodynamic internal degrees of freedom; Thermal diffusion.