Thermodynamics of Vaporization and High Temperature Enthalpy of Zirconium Tetraiodide

Autor: M. J. Ferrante, K. H. Lau, D. Cubicciotti
Rok vydání: 1978
Předmět:
Zdroj: Journal of The Electrochemical Society. 125:972-977
ISSN: 1945-7111
0013-4651
DOI: 10.1149/1.2131601
Popis: The sublimation of was studied by a torsion effusion‐gravimetric technique in which the molecular weight of the effusing gas and its pressure in the effusion cell were measured simultaneously. The sublimation pressures of were found to depend on the orifice size of the effusion cell. The measured pressures were extrapolated to zero orifice size to obtain the equilibrium vapor pressures, which could be represented by the equationEnthalpies above room temperature, up to 703.1°K for solid zirconium tetraiodide were measured in a copper‐block, drop calorimeter. The enthalpy increments above 298.15°K were expressed by the equationThe data were combined with literature vapor pressure data obtained at higher temperatures and a second law treatment used to derive the enthalpy and entropy of sublimation (31.88 kcal/mole and 46.9 cal/mole‐degree, respectively, at 298°K). These values were used to evaluate the enthalpy of formation of gaseous (−84.9 kcal/mole) and the absolute entropy of solid 59.8 cal/mole‐degree) at 298°K.
Databáze: OpenAIRE