[en] Rates of carbon gasification in O² and CO² are dependent upon the active surface area of the carbon. That is, only some fraction of the total surface area is active at dissociatively chemisorbing molecues of O² and CO², which is the first step leading to ultimate carbon gasification by these gases. This research is concerned about measuring the concentration of active sites on carbons varying in crystallite size and orientation (that is, all the way from microporous carbons of poor crystallinity to natural graphite flakes of high crystallinity) and relatig this concentration to gasification rates. It is seen that oxygen build-up on carbon during gasification can greatly exceed that held just on active sites, measured by oxygen chemisorption in the absence of gasification. It is attributed to spillover of oxygen from prismatic planes (active sites) onto the basal planes. Both gasification rates for the C-O² reaction and oxygen spillover are enhanced by the presence of a catalyst, platinum, on the carbon surface. In an effort to simplify active site characterization, an exchange reaction of oxygen between CO²₁₈^-₁₈ and CO²₁₆^-₁₆, over active sites, to form CO²₁₆^-₁₈ was to be followed under conditions where build-up of oxygen complexes on carbon is negligible. Results of this study are reviewed