Entropy Gibbs’ research

Note that the volume changes for the last two processes are identical. We note also that for the liquid phases at room temperature k1t is much smaller than 1 atm-1 (e.g., for water at 0°C, kTxT 1 cm3 mol-1, AV 20 cm3 mol-1, and kT / atm w2x 104cm3 mol-1). Similarly, in equation (7.73) k1t < i P-1 (the limit of an ideal-gas phase). Thus, the volume change for the three standard processes is dominated by the terms which originate from the ideal-gas compressibility. Because of this undesirable feature, it is common to abandon these processes when studying the volume of solvation. Almost all researchers who study the solvation phenomena apply one of these standard processes for quantities like the Gibbs energy, entropy and enthalpy of... 

There are rival theories of the glass transition the Gibbs Dimarzio theory assumes that the configurational entropy of the chains approaches zero at Tg. Other researchers prefer a mode coupling theory (MCT), based on the dynamics of density fluctuations. However, it is difficult to extract a simple physical meaning from the complex equations that describe correlations between density fluctuations. Neither theory, at its current state of development, is particularly useful in understanding the properties of glassy polymers. 

In this chapter we have discussed several more detailed aspects of the entropy of water. This is an exciting area of research and much remains to be understood or accomplished, at the level of both theoretical calculation of entropy and experimental determination of its value. We have focused on two oft-used expressions, one due to Rosenfeld and the other due to Adam and Gibbs, and tried to provide a bit of understanding of both. We discuss several recent schemes proposed to discuss the entropy of water. These new schemes provide fairly accurate values of entropy for bulk water and are expected to be semi-quantitatively accurate for water in complex systems. 

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