1.23.2: Water: Molar Volume
The molar volume \(\mathrm{V}_{1}^{*}(\ell)\) and density \(\rho_{1}^{*}(\ell)\) of water(\(\ell\)) are intensive properties. The \(\mathrm{p}-\mathrm{V}-\mathrm{T}\) properties of water are perhaps the most extensively studied. Two properties are almost universally known;
- the molar volume of water at ambient pressure and \(273.15 \mathrm{~K}\) is less than that of ice, and
- the molar volume of water at \(273.15 \mathrm{~K}\) decreases on heating to reach a TMD before increasing.
At ambient pressure the temperature of maximum density for water, \(\mathrm{TMD} = 3.98 \text { Celsius}\); for \(\mathrm{D}_{2}\mathrm{O}\), \(\mathrm{TMD} = 11.44 \text { Celsius}\). The \(\mathrm{TMD}\) for \(\mathrm{SiO}_{2}\) is around 15270 Celsius, the dependence of density on temperature being less marked about the \(\mathrm{TMD}\) than that for water [1].
The dependence of \(\mathrm{V}^{*}\left(\mathrm{H}_{2} \mathrm{O} ; \ell\right)\) on temperature and pressure is reported by many laboratories. Most accounts cite the study reported by Kell and Whalley in 1965, later extended in 1978 [2,3]. Kell has examined the results in detail [4]. The \(\mathrm{TMD}\) has, of course, attracted considerable attention. Nevertheless the \(\mathrm{TMD}\) has no deep significance in the context of understanding the properties of water(\(\ell\)). Other properties of water(\(\ell\)) show extrema at other temperatures; e.g. isothermal compressibility near \(300 \mathrm{~K}\) [5-7].
Footnotes
[1] C. A. Angell and H. Kanno, Science, 1976, 193 ,1121.
[2] G. S. Kell and E. Whalley, Philos. Trans. R. Soc. London, 1965, 258 ,565.
[3] G. S. Kell, G. M. McLaurin and E.Whalley, Proc. R. Soc. London, Ser. A,1978, 360 ,389.
[4] G. S. Kell, J. Chem. Eng. Data, 1967,12,66; 1975,20,97; 1970, 15 ,119.
[5] R.A. Fine and F. J. Millero, J.Chem.Phys.,1975,63,89; 1973, 59 ,5529.
[6] D.-P. Wang and F. J. Millero, J.Geophys. Res., 1973, 78 ,7122.
[7] F. J. Millero, R. W. Curry and W. Drost-Hansen, J. Chem. Eng. Data, 1969, 14 ,422.