Water properties

Standard properties of water relevant in the context of ionic solvation (book Table 1.1). The reported data includes the molar mass M, the mass density ρɵ, the macroscopic surface tension coefficient γɵ, the static relative dielectric permittivity εɵ, the infinite-frequency relative dielectric permittivity εɵ, the gas-phase molecular dipole moment μd,gɵ, the liquid-phase (average) molecular dipole moment μd,lɵ, the solid-phase (average; hexagonal ice Ih) molecular dipole moment μd,sɵ, the triple point pressure Pt and temperature Tt, the critical point pressure Pc and temperature Tc, the melting temperature Tmο, the boiling temperature Tbο, the melting enthalpy ΔmHο at Tmο, the vaporization enthalpy ΔbHο at Tbο, the vapor pressure Pvap-, the formation free energy ΔfGɵ, the formation enthalpy ΔfHɵ, the formation entropy ΔfSɵ, the absolute molar entropy sɵ, the molar isobaric heat capacity cPɵ, the molar volume vɵ, the isothermal compressibility κTɵ, the isobaric expansivity αPɵ (thermal expansion coefficient), the molar volume-compressibility kTɵ and the molar volume-expansivity aPɵ. The first pressure (∂P) and temperature (∂T) derivatives, as well as the corresponding second derivatives (∂2P, ∂2T, ∂2P,T), are also reported for some properties. The standard states are according to the bbmeT convention (reference pressure Pο=1 bar and reference temperature T-=298.15 K).

Property                                    Unit                                           Value                                   Notes

(a) the value reported for the pressure Pο=1 bar is approximated here by a value reported for a pressure P=1 atm; (b) calculated as ∂Pρɵɵ κTɵ ; (c) calculated based on an empirical analytical equation for ρ-(P) ; (d) calculated as ∂Tρɵ=-ρɵ αPɵ ; (e) calculated based on an empirical analytical equation for ρο(T) ; (f) calculated from the temperature derivative of the isothermal compressibility of water, based on an empirical analytical equation for κTο(T), as ∂2P,TρɵɵT κTɵ+(ρɵ)-1PρɵTρɵ ; (g) calculated based on an empirical analytical equation for γο(T) ; (h) an alternative value based on an empirical analytical equation for εο(T) is 0.164·10-2 K-2 ; (i) a (probably less accurate) value estimated by a finite temperature difference of the pressure derivatives, based on two empirical analytical equations for εS(P) at T=273 and 323 K is -2.81·10-5 K·bar-1 ; (j) the reported value corresponds to ΔbHο at Tbο (both approximated here by values at 1 atm rather than 1 bar), whereas the value ΔbHɵ (i.e. the standard value at Pο and T-, which is not on the boiling curve of the phase diagram) is 43.98 kJ·mol-1 ; (k) calculated using the Gibbs equation (ΔfGɵfHɵ-T-ΔfSɵ); (l) calculated from M and ρɵ as vɵ=(ρɵ)-1 M ; (m) calculated from κTɵ and vɵ as kTɵ=vɵ κTɵ ; (n) calculated from αPɵ and vɵ as aPɵ=vɵ αPɵ.

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