Some Thermodynamic Properties of Pure and Impure Nitrogen

Boiling points, freezing points, and vapor pressures (from 56 K to the normal boiling point) for pure and various doped N2 samples have been measured. The normal boiling points for N2 and N2 doped with 100 v.p.p.m. of O2, Ar, Kr, and CO impurities were found to be 77.3439 K, 77.3458 K, 77.3452 K, 77.3454 K, and 77.3444 K respectively. The triple points of the same samples are 63.14635 K, 63.1445 K, 63.14575 K, 63.1487 K, and 63.14675 K respectively. The values obtained for the heats of sublimation, vaporization, and fusion at the triple point of pure N2 were 6773.8, 6049.6, and 724.3 J/mole respectively and the above impurities changed these quantities by the amounts given in Tables 5 and 6.