Thermodynamic Behaviour of Fluids near Critical Points compressible liquid mixtures [Pg.345]

The description of thermodynamic anomalies observed near critical points has been presented in many books and reviews [124-135]. Sufficiently close to a critical point, thermodynamic properties A vary as simple power laws of the distance e from the critical point. [Pg.173]

Sengers, J. V. Levelt-Sengers, J. N. H., Thermodynamic behavior of fluids near the critical point, Ann, Rev. Phys. Chem. 1986, 37, 187-222 [Pg.385]

The form of equations (8.11) and (8.12) turns out to be general for properties near a critical point. In the vicinity of this point, the value of many thermodynamic properties at T becomes proportional to some power of (Tc - T). The exponents which appear in equations such as (8.11) and (8.12) are referred to as critical exponents. The exponent 6 = 0.32 0.01 describes the temperature behavior of molar volume and density as well as other properties, while other properties such as heat capacity and isothermal compressibility are described by other critical exponents. A significant scientific achievement of the 20th century was the observation of the nonanalytic behavior of thermodynamic properties near the critical point and the recognition that the various critical exponents are related to one another [Pg.395]

Hassan Behnejad, Jan V. Sengers, and Mikhail A. Anisimov, Thermodynamic Behaviour of Fluids near Critical Points. In A. R. H. Goodwin, J. V. Sengers, and C. J. Peters, editors. [Pg.511]

Other quantities associated with second derivatives of the thermodynamic potential are also enhanced near the critical point demonstrating typical 1 / / l behavior, cf. [21], However numerical coefficients depend strongly on what quantity is studied. E.g. fluctuation contributions above Tc to the color diamagnetic susceptibilities [Pg.290]

It is now established both theoretically and experimentally that many thermodynamic variables assume a simple power-law behaviour at or near critical points in both pure and mixed fluids. The actual functional dependence of one variable on another can be characterized by the so-called critical indices a, 5, etc. The critical index j8, for example, defines both the shape of the gas-liquid coexistence curve for a pure fluid and the liquid-liquid coexistence curve of a binary mixture in the vicinity of either an upper or a lower critical solution temperature. The correspondence between critical phenomena in one-, two-, [Pg.149]

Anisimov, M.A., Gorodetskii, E.E., Kulikov, V.D., and Sengers, J.V. (1995) A gen-eral isomorphism approach to thermodynamic and transport properties of bin2u y fluid mixtures near critical points, Physica A 220, 277-324. [Pg.121]

This chapter deals with critical phenomena in simple ionic fluids. Prototypical ionic fluids, in the sense considered here, are molten salts and electrolyte solutions. Ionic states occur, however, in many other systems as well we quote, for example, metallic fluids or solutions of complex particles such as charged macromolecules, colloids, or micelles. Although for simple atomic and molecular fluids thermodynamic anomalies near critical points have been extensively studied for a century now [1], for a long time the work on ionic fluids remained scarce [2, 3]. Reviewing the rudimentary information available in 1990, Pitzer [4] noted fundamental differences in critical behavior between ionic and nonionic fluids. [Pg.2]

In the previous sections we have discussed stability of a thermodynamic state in the face of fluctuations. But the theory that we presented does not give us the probability for a fluctuation of a given magnitude. To be sure, our experience tells us that fluctuations in thermodynamic quantities are extremely small in macroscopic systems except near critical points still we would like to have a theory that relates these fluctuations to thermodynamic quantities and gives us the conditions under which they become important. [Pg.323]

The interesting assumption in this analysis is the way in which the velocity or flux is assumed to vary with the chemical potential gradient. This type of assumption is made frequently in studies of diffusion. It is central to the development of irreversible thermodynamics, and so it is at the core of the theories of multicomponent diffusion described in Chapter 7. Interestingly, it is known experimentally to be wrong in the highly nonideal solutions near critical points (see Section 6.3). [Pg.130]

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