A thermodynamic consistency test based on the "local area" test is developed which permits analysis of vapor-liquid equilibrium data in terms of measurement uncertainties in the independent variables. The effect of random measurement errors on the consistency test and on the uncertainty in the activity coefficients is illustrated. Uncertainty in the measurement of liquid composition may cause large uncertainty in the activity coefficients but be difficult to detect by means of consistency test. Comparing the test results to the null value is shown to be of less value than comparison with the bounds of a confidence region.

The fraction of molecules that vaporize from a surface and escape through a cylindrical hole to a condenser (escape probability) has been calculated by Monte Carlo methods for the case of hemispherical (concave and convex) and flat surfaces. The results for vaporization from the flat surface are in agreement with results predicted by the Clausing factor. The effect of condensation coefficients has also been investigated. A semiempirical equation of adjustable parameters was developed which represents the escape probabilities as a function of the length-to-radius ratio (L / R) and the condensation coefficient (α).

Methods are developed and illustrated for determining the amount of nonsatisfaction of the overall area (integrated Gibbs‐Duhem equation) test for vapor‐liquid equilibrium data that is to be expected on the basis of random experimental uncertainties. Data which satisfy the overall test within these limits, as well as the local area test, are said to be consistent within the bounds established by their experimental uncertainties, while data which do not are said to show significant systematic error and hence are termed inconsistent.

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Y = viscosity vw LITERATURE CITED = viscosity, defined by Equation (2)