Vapor Pressure of Antimony by the Torsion‐Effusion Method

Autor:	C. Ernest Birchenall, Gerd M. Rosenblatt
Rok vydání:	1961
Předmět:	Chemistry Vapor pressure Inorganic chemistry Analytical chemistry General Physics and Astronomy chemistry.chemical_element Enthalpy of vaporization Zinc Mercury (element) Monatomic ion Antimony Knudsen number Physical and Theoretical Chemistry Third law of thermodynamics
Zdroj:	The Journal of Chemical Physics. 35:788-794
ISSN:	1089-7690 0021-9606
DOI:	10.1063/1.1701217
Popis:	The pressures and mean molecular weights of the vapors over solid antimony (420–550°C) and solid zinc (250–335°C) have been determined by simultaneous measurements by the torsion‐momentum and Knudsen weight loss methods. The torsion measurement was calibrated with mercury at 30° using a mercury vapor pressure of 2.96×10‐3 mm Hg determined by concurrent weight loss experiments. Zinc vapor is confirmed to be monatomic. The zinc pressure data are represented by logPmm=(8.741±0.218) — (6630±125) /T giving ΔH298° (vap)=30.73±0.57 and 31.18±0.12 kcal/mole by the second law and third law of thermodynamics, respectively, in excellent agreement with previously reported results. The vapor over solid antimony is all Sb4 molecules within experimental error. Least‐squares analysis of the antimony data yields logPmm=(10.571±0.090) — (10 300±68) /T, pressures 10%‐40% lower than those previously reported. The heat of vaporization of Sb4(g) at 298.16°K is 49.83±0.31 kcal/mole by the second law and 49.45±0.09 by the third law of thermodynamics. This thermodynamic consistency and the agreement of the zinc results with accepted measurements indicate that the antimony pressures presented should be preferable to those previously reported.
Databáze:	OpenAIRE
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