The approximate analytical solutions for integral equations including gamma distribution on the chemisorption rate constant as well as gamma, normal, or uniform distribution functions on the distance between neighboring sites, taking into account the lateral interaction between chemisorbed species in mean-field approximation, for kinetic isotherms on an amorphous random and patchwise heterogeneous solid surface have been obtained. Influence of parameters of these functions on the shape of simulated kinetic isotherms and on the moments of distribution on observable rate constants have been studied. Satisfactory agreement between the present model predictions and experimental kinetic isotherms obtained for the chemisorption of organosilicon compound on the surface of pyrogenic silica has been found.