The aim of this laboratory activity is to provide students with a practical understanding of the concept of fugacity through a hands-on learning approach. Rather than using the traditional method of calculating the gas fugacity by employing a parametrized equation of state in the classroom, we propose an alternative and more realistic strategy. This approach involves measuring the compressibility factor of a gas and using the results to evaluate its fugacity as well as its second virial coefficient. While this method can be used to analyze other gases, the present study focuses on determining the fugacity of CO2 as a function of pressure and temperature in conditions where the system’s nonideality is significant. The apparatus employed in the measurement is a highly simplified and safer variation of previous implementations. A sampling loop connected to a six-port injector, as those used in the field of HPLC chromatography, eliminates any possibility of sudden discharge of large amounts of gas, and hence a risk of explosion, due to incorrect valve operation.
Bikiel et al. (2026) studied this question.