Accession Number : ADD095334

Title :   Computer Programs for the Evaluation of Activity and Osmotic Coefficients.

Descriptive Note : Final rept.,

Corporate Author : NATIONAL STANDARD REFERENCE DATA SYSTEM

Personal Author(s) : Staples, Bert R ; Nuttall, Ralph L

Report Date : Dec 1976

Pagination or Media Count : 59

Abstract : A number of specialized computer programs have been developed for the purposes of calculating thermodynamic properties directly from experimental data and for subsequent data manipulation, including non-linear least squares fitting of the data to empirical or semi-empirical equations that describe the function over a range of compositions, temperatures or other parameters. The details of the programs used in the critical evaluation of mean activity and osmotic coefficients and sample runs for each program are discussed. Osmotic coefficients can be calculated from direct vapor pressure measurements or from isopiestic molalities. Activity coefficients can be calculated from electromotive force measurements of galvanic cells, both without liquid-junction and with transference. A non-linear least-squares program fits data from all sources as a function of phi and log of gamma. Once the parameters of the fitting equation have been obtained, another program can be used to calculate a table of m, gamma, phi, aw, and delta Gex at rounded molalities. (Author)

Descriptors :   *COMPUTER PROGRAMS, *TEST AND EVALUATION, *OSMOTIC PRESSURE, *COEFFICIENTS, *LEAST SQUARES METHOD, EQUATIONS, FITTINGS, CURVE FITTING, NONLINEAR ALGEBRAIC EQUATIONS, VAPOR PRESSURE, PRESSURE MEASUREMENT, OSMOSIS, THERMODYNAMIC PROPERTIES

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE