The modeling of oxygen chemisorption kinetics with the assumption that there is a distribution of activation energies for adsorption is discussed. Two different types of heterogeneous surfaces are considered : in one case, it was assumed that the surface has an a priori distribution of activation energies for adsorption whereas in the second case, it was assumed that the activation energy increases as a consequence of oxygen chemisorption (i.e., due to induced heterogeneity). For each model, the activation energy was assumed to vary linearly with coverage. It was found that the adsorption curves obtained from each model are essentially similar and that the use of one or the other can be largely dictate by computational convenience. For example, the Tokoro[4,5] model can be regressed in a straight forward manner to obtain model parameters from the data and can be readily modified to include the effects of intra-particle diffusion or bulk phase mass transfer on the kinetics. Based on an analysis of experimental chemisorption data, it can be concluded that the activation energy for oxygen chemisorption on a microporous char is in the range of 12-32 kcal/mole. The models can correctly account for the oxygen partial pressure dependence of the chemisorption data.