Evaporation and condensation of vapor‐gas mixture is studied on the basis of the kinetic BGK–Morse model equation. The linearized kinetic model equation is solved using the half‐range Hermite polynomials and various slip coefficients are obtained. The obtained slip coefficient of vapor pressure is insensitive to the variation in concentration of a noncondensable gas. When the mean concentration of noncondensable gas is very small, an exponential distribution of noncondensable gas is obtained and a set of nonlinear equations is transformed to that of linear equations for pure vapor. It is found from the linear and nonlinear solutions that the impedance of mass flux in the two‐surface problem is composed of surface and induced resistances and that the latter is proportional to the total amount of the noncondensable gas rather than the mean concentration of it.