MEASUREMENT AND CORRELATION OF THE (P, RHO, T) RELATION OF NITROGEN .1. THE HOMOGENEOUS GAS AND LIQUID REGIONS IN THE TEMPERATURE-RANGE FROM 66 K TO 340 K AT PRESSURES UP TO 12 MPA

Comprehensive (p, rho, T) measurements on pure nitrogen have been carr ied out in the single-phase region (920 values) and along the entire ( vapour + liquid) coexistence curve (159 values). The results reported in this first paper cover the homogeneous gas and liquid region in the temperature range from 66 K to 340 K at pressures up to 12 MPa. The t otal uncertainty of the measurements in density rho is <(\0.9.10(-4).r ho\ to \1.5.10(-4).rho\) with the exception of the temperature range f rom 123 K to 140 K (T-c = 126.192 K) at densities between 150 kg.m(-3) and 450 kg.m(-3), where the total uncertainty in pressure p is <(\0.8 .10(-4).p\ to \3.0.10(-4).p\). Values for the second and third virial coefficients have been determined from the measurements in the homogen eous gas region of nitrogen. The experimental results are compared wit h the results Of previous workers. (C) 1997 Academic Press Limited.