Parameters of State in the Global Thermodynamics of Binary Ideal Gas Mixtures in a Stationary Heat Flow

In this paper, we formulate the first law of global thermodynamics for stationary states of the binary ideal gas mixture subjected to heat flow. We map the non-uniform system onto the uniform one and show that the internal energy [Formula: see text] is the function of the following parameters of state: a non-equilibrium entropy [Formula: see text] , volume V, number of particles of the first component, [Formula: see text] , number of particles of the second component [Formula: see text] and the renormalized degrees of freedom. The parameters [Formula: see text] , [Formula: see text] satisfy the relation [Formula: see text] ([Formula: see text] and [Formula: see text] are the degrees of freedom for each component respectively). Thus, only 5 parameters of state describe the non-equilibrium state of the binary mixture in the heat flow. We calculate the non-equilibrium entropy [Formula: see text] and new thermodynamic parameters of state [Formula: see text] explicitly. The latter are responsible for heat generation due to the concentration gradients. The theory reduces to equilibrium thermodynamics, when the heat flux goes to zero. As in equilibrium thermodynamics, the steady-state fundamental equation also leads to the thermodynamic Maxwell relations for measurable steady-state properties.