A New Model for Specific Heat Capacity of Real Gas

Abstract

Based on the new thermodynamic theory, a new model was suggested to calculate the specific heat capacities of monoatomic gas, He, and diatomic gas, O₂. The theory suggests a portion of gas molecules with the highest kinetic energy affords the heat exchange to sustain the state equilibrium by inelastically colliding and liquefying on the container walls, whereas the rest elastically colliding with walls creates pressure. Accordingly, a general equation of specific heat capacity is established on the density of liquid and gas. Given at isobar and at isochore, C_p and C_v at any temperature can be calculated with the densities of gas and liquid (or solid). Employing the available data of He and O₂ issued by NIST, C_ps, and C_vs are calculated. The results fit the reference data well.