Based on the statistical theory of the rate of interfacial transport, a standard procedure is proposed for developing equations for adsorption kinetics and equilibria, corresponding to some model of a heterogeneous solid surface. By replacement of a certain function by another, in a kind of master equation, the isotherm equation is transformed into corresponding equation for adsorption kinetics, and vice versa. The detailed form of that master equation is related to the form of the adsorption energy distribution. The theoretical origin of the popular empirical equations for adsorption kinetics is reexamined and the range of their applicability is shown. The present theoretical treatment is limited to lower surface coverages where collective character of adsorption can be ignored, along with the readsorption kinetics.