Evaluation of a simple static method for measuring vapor pressure
| Autor: | Thomas B. Douglas, Ralph F. Krause |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
Argon
True vapor pressure Vapor pressure Saturation vapor density Vapour pressure of water Analytical chemistry chemistry.chemical_element Thermodynamics Atomic and Molecular Physics and Optics Superheating Volume (thermodynamics) chemistry General Materials Science Density of air Physical and Theoretical Chemistry |
| Zdroj: | The Journal of Chemical Thermodynamics. 9:511-522 |
| ISSN: | 0021-9614 |
| DOI: | 10.1016/0021-9614(77)90155-0 |
| Popis: | To complement transpiration and other methods when applied to partially dissociated or associated vapors, a direct static method was developed for measuring vapor pressures of around 1 kPa. A valve brings argon, originally at a little higher pressure, into direct contact with the pure vapor, whose pressure is very simply calculated from the reduction in pressure of the argon. Several types of systematic error were estimated; these include especially the effects of diffusion, viscosity, and steady-state gradients in gas temperature and molar mass, and indicate suitable dimensions of the capillary admitting the argon such that the vapor will remain confined essentially to its original volume during the time required for total-pressure equilibration. To test the method and apparatus, the vapor pressures of I 2 at 343 and 353 K (using saturated vapor) and that of MoF 6 at 237 K (using “superheated” vapor) were measured. The three mean values agree to better than 1 per cent with the most reliable published values, which themselves probably have absolute uncertainties this great. Further refinement of the method to give a general accuracy of 0.1 per cent seems feasible. |
| Databáze: | OpenAIRE |
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