This paper discusses sources of hard coal energetic heterogeneity and its effects on sorption properties. Natural coal is viewed as a porous elastic copolymer in which absorption and adsorption phenomena can occur. The dominant role of submicropores which are about the size of a water molecule is stressed, as the effects of larger pores on sorption capacity are negligible. Bearing in mind the size of the submicropores, one must take account of swelling of the sorbent and the resultant changes in its surface area. A unified theoretical description of sorption equilibria with respect to swelling phenomena (multiple sorption model) is developed. Alternative models describing effects of geometrical and chemical factors on the sorption energy are discussed. The resultant theoretical sorption isotherms are compared with empirical data for sorption of water and benzene in two coals. The model explains differences in sorption properties of the coals in terms of the pecularities of their surfaces. Expansion was found to be of crucial importance for the sorption of benzene. It is shown that a simplified description of sorbent-sorbate energetic interactions is adequate to express the basic relations between the energies attributed to submicropores of different; size.