Physical adsorption errors accumulate in the isothermal Burnett PvT apparatus. The equations describing this sequential phenomena plus diagnostic methods and correction procedures are given. Shift of the apparent volume ratio, the prinicipal indication of significant adsorption, is related to the difference between the surface and volume ratios. The effect of adsorption on the usual Burnett graphs follows from real and simulated data examples. Isochoric coupling as related to the adsorption problem is fully reviewed.
Experiences with chemisorption are related and explained for the first time. Molecular association, which is properly measured by the Burnett apparatus, is compared to adsorption where the two phenomena coexist.