The Rate of Decomposition of Nitrogen Pentoxide at Very Low Pressures

Abstract

In a previous article [1] the results have been reported of some experiments on the rate of decomposition of gaseous nitrogen pentoxide at moderately low pressures in the range 0.2 to 2 mm. of mercury. The special features of the experimental method employed, included the use of a very large reaction vessel constructed from a 45-liter flask, thus minimizing the effect of the walls, and the use of a specially sensitive "click" gauge to follow the reaction by direct pressure measurements, thus avoiding the dangers involved in following the reaction by periodically freezing out the oxides of nitrogen and measuring the evolved oxygen, as has sometimes been done. The results obtained at these moderately low pressures showed no falling-off in the specific unimolecular rate of decomposition below that obtained at high pressures. In the present article we desire to report the results of some further experiments on the rate of decomposition of nitrogen pentoxide at total initial pressures down to 0.0055 mm.