SECOND VIRIAL COEFFICIENTS AND INTERMOLECULAR FORCES FOR THE AMMONIA–ACETYLENE SYSTEM

Abstract

Volumetric data for gaseous ammonia–acetylene mixtures have been analyzed to obtain second virial coefficients as a function of temperature and composition. From the pure-component virial coefficients of ammonia and acetylene, Kihara-potential parameters were obtained and these were used to calculate the physical contributions to the second cross virial coefficients, B 12 . The difference between the experimental B 12 and that calculated from the physical contribution is attributed to chemical interaction, or complex formation, between the two molecules. Chemical equilibrium constants have been calculated, and ΔH 0 and ΔS 0 for complex formation were found to be −(2 210) cal/mole and −16.6 cal/mole °K respectively. These results indicate very weak hydrogen bond formation between the nitrogen atom in the ammonia and the hydrogen atom in acetylene.