THE DETERMINATION OF THE SATURATION VAPOR PRESSURE OF SOLID HYDROXYLAMINE USING A PISTON PRESSURE GAUGE

Abstract

The saturation vapor pressure of solid hydroxylamine has been determined at temperatures from −12 to 7° C and found to fit the equation[Formula: see text]From this have been calculated several thermochemical quantities, including a heat of sublimation of 15.34 kcal/mole, and a dissociation energy of 61.3 kcal/mole for the NH2—OH bond. Vapor density measurements showed that hydroxylamine vapor consisted of single molecules of NH2OH at 0.27 Torr and 25 °C.A novel pressure gauge used in the measurements is described. Pressures were determined with an accuracy of ±0.001 Torr by measuring the force acting on a piston, moving freely in a glass cylinder, suspended on the arm of a torsion balance.