Convergence of the virial expansion for an associated gas

Vapor Pressure and Heat of Vaporization of Molecules That Associate in the Gas Phase

“…As the available vapour pressure experiments for CH 3 COOH are of similar or lower accuracy, this is a reasonable approximation. Substituting Eqs (2),( 8) and (5) in (9), V m l being neglected, and using the relations (7) and p = K d y(1+y)…”

“…section S8 in the Supporting Information for a list of symbols). The equation of state of such a gas is obtained by solving the mass balance 1/ V m g = p 1 / RT + 2 p 2 / RT , Dalton’s law p = p 1 + p 2 , and the equilibrium condition described by eq for p 1 , p 2 , and V m g (the molar volume defined with respect to the total number of molecules in the gas phase, contained in both monomers and dimers); the result for V m g reads …”

“…This constitutive relation has been derived many times in various forms, − but is due to Gibbs . In the limit of weakly dimerized gas ( p ≪ K d ), it simplifies to the virial expansion: …”