The equation of state and heat capacity of nitrogen at high pressures determined from speeds of sound

Abstract

The equation of state and heat capacity of nitrogen have been determined at temperatures from 123.15 K to 298.15 K and at pressures from 200 MPa to 1000 MPa using a new computational method. This is based on stepwise construction of p ( T ) isochores starting from an experimental reference p ( ρ ) isotherm and using the previously reported speeds of sound of nitrogen as a function of pressure and temperature. In the region of overlap, the calculated densities are found to be in good agreement with those obtained from the most accurate direct measurement reported in the literature.