Stefan-Maxwell relations for multicomponent diffusion and the Chapman-Enskog solution of the Boltzmann equations

It is established that corrections factors for higher order Chapman-Enskog approximations to multicomponent diffusion coefficients are equal for a given N-component gas mixture. This enables us to invert the mass flux equations for the diffusion forces and obtain the Stefan-Maxwell equations in any Chapman-Enskog approximation. The impedance matrix for these equations is symmetric regardless of whether or not the multicomponent diffusion coefficients are symmetric. Further, the impedance matrix is the same whether one chooses to invert mass flux equations involving symmetric or asymmetric diffusion coefficients.