Accession Number:

AD0844941

Title:

Preliminary Report on the Thermodynamic Properties of Selected Light-Element and Some Related Compounds.

Descriptive Note:

Preliminary rept.,

Corporate Author:

NATIONAL BUREAU OF STANDARDS GAITHERSBURG MD

Report Date:

1968-07-01

Pagination or Media Count:

125.0

Abstract:

This report presents in detail the methods, results, and interpretation of six recent NBS experimental investigations of thermodynamic and related properties. Measurements of the heats of reaction with hydrogen of chlorine trifluoride and its two free elements gave on preliminary calculation 38.61 kcalmol, which agrees with two published values and disproves a formerly credited value that is 10 kcalmol less exothermic. Precise measurements of the heat capacity of sintered beryllium oxide gave generally lower heat capacities and an appreciably lower entropy than previously accepted. A new millisecond apparatus for measuring simultaneously the heat capacity, electrical resistivity, and hemispherical total emittance of electrical conductors is described. Preliminary results are given for molybdenum 1800-2800 K. The reaction between beryllium metal and aluminum oxide was studied mass-spectrometrically 1511-1743 K. The resulting second-law and third-law heats of four reactions involving the gas species Be, Al, O, Al2O, and AlO are compared. From a continuation of the spectroscopic investigation of the alkali-hydroxide molecules, the high-temperature microwave spectra of RbOH and the matrix-isolation infrared spectra of RbOH and NaOH plus the deuteroxides in all cases were observed, and are analyzed to give bond lengths, frequency fundamentals, nuclear quadrupole coupling constants, and vibration-rotation interaction constants. The essentially linear shapes and unusual bending potentials of these molecules are very similar to those found earlier for CsOH, and suggest a similar behavior of all the alkali hydroxides. Author

Subject Categories:

  • Atomic and Molecular Physics and Spectroscopy
  • Thermodynamics
  • Rocket Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE