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A Helmholtz Free Energy Formulation of the Thermodynamic Properties of the Mixture (Water + Ammonia)



R Tillner-Roth, Daniel G. Friend


A thermodynamic model incorporating a fundamental equation of state for the Helm-holtz free energy of the mixture water+ammonia} is presented which covers the thermodynamic space between the solid-liquid-vapor boundary and the critical locus. It is also valid in the vapor and liquid phases for pressures up to 40 Mpa. It represents vapor-liquid equilibrium properties with an uncertainty of 0.01 in liquid and vapor mole fractions. Typical uncertainties in the single-phase regions are 0.3% for the density and 200 J mol-1 for enthalpies. Details of the data selection and the optimization process are given. The behavior of the fundamental equation of state is discussed in all parts of the thermodynamic space.
J. Phys. & Chem. Ref. Data (JPCRD) -
No. 1


ammonia-water, equation of state, Helmholtz free energy, thermodynamic properties


Tillner-Roth, R. and Friend, D. (1998), A Helmholtz Free Energy Formulation of the Thermodynamic Properties of the Mixture (Water + Ammonia), J. Phys. & Chem. Ref. Data (JPCRD), National Institute of Standards and Technology, Gaithersburg, MD (Accessed July 19, 2024)


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Created July 31, 1998, Updated October 12, 2021