Measurement of the temperature variation of virial coefficients. I. Application to the second virial coefficient of n-butane

Abstract

An unconventional apparatus, described in detail, determines, through a measured small volume increment, the temperature dependence of the second virial coefficient of a vapour without the necessity for isothermal expansion. Absolute pressure determinations are avoided by working differentially, vapour against nitrogen reference gas. Results for n-butane at 0-150° agree with established work.