In the present paper solution of two problems is presented on recondensation in a plane layer with noncondensing gas and on condensation-evaporation at the boundary of a semi-infinite vapour-gas mixture volume. The solution is based on kinetic theory methods involving very simple model kinetic equations. In part 1 the properties of the model are investigated as well as the possibility of its application to the analysis of transfer processes in a classical binary mixture. A set of moment equations is composed for description of such processes. Part 2 contains the solution of the above problems. In the problem of recondensation, expressions are obtained describing a mass flow and concentration fields in the whole range of Knudsen numbers 0 < Kn < ∝. In the problem of temperature slip, a mass flow, temperature discontinuity and partial density “jump” are given as the functions of concentration, ratios of molecular mass components and condensation coefficient. The results obtained are extensions and specifications of more special works by different authors.