Chemical potential significance

Perhaps the most significant of the partial molar properties, because of its appHcation to equiHbrium thermodynamics, is the chemical potential, ]1. This fundamental property, and related properties such as fugacity and activity, are essential to mathematical solutions of phase equihbrium problems. The natural logarithm of the Hquid-phase activity coefficient, Iny, is also defined as a partial molar quantity. For Hquid mixtures, the activity coefficient, y, describes nonideal Hquid-phase behavior. 

Reactor design is particularly critical, because reactors involve chemical transformations and often potentially significant energy releases. 

The structure of this equation suggests that we associate //+ with the chemical potential of cations and [a++p+(F) + a+ p (F)] with the logarithm of the activity coefficient relative to cations in the MFA. In addition to their thermodynamic significance, these coefficients characterize the symmetry of... 

Equations 6 and 7 determine the composition and chemical potential of the solvent in a clathrate as a function of the variables, Eq. 2. Their physical significance can best be appreciated if we... 

In Chapter 6, fugacity and activity are defined and described and related to the chemical potential. The concept of the standard state is introduced and thoroughly explored. In our view, a more aesthetically satisfying concept does not occur in all of science than that of the standard state. Unfortunately, the concept is often poorly understood by non-thermodynamicists and treated by them with suspicion and mistrust. One of the firm goals in writing this book has been to lay a foundation and describe the application of the standard state in such a way that all can understand it and appreciate its significance and usefulness. 

In contrast to the Gibbs ensemble discussed later in this chapter, a number of simulations are required per coexistence point, but the number can be quite small, especially for vapor-liquid equilibrium calculations away from the critical point. For example, for a one-component system near the triple point, the density of the dense liquid can be obtained from a single NPT simulation at zero pressure. The chemical potential of the liquid, in turn, determines the density of the (near-ideal) vapor phase so that only one simulation is required. The method has been extended to mixtures [12, 13]. Significantly lower statistical uncertainties were obtained in [13] compared to earlier Gibbs ensemble calculations of the same Lennard-Jones binary mixtures, but the NPT + test particle method calculations were based on longer simulations. 

HTFT syncrude also has significant chemicals potential, especially when olefins and oxygenates are targeted. 

LTFT syncrude has significant chemicals potential in the field of linear paraffins and waxes, with some potential for olefin and oxygenate chemicals too. It is also well suited for the production of lubrication oils by catalytic dewaxing. 

Chemical potentials for the constituents of minerals are defined in a similar manner. All minerals contain substitutional impurities that affect their chemical properties. Impurities range from trace substitutions, as might be found in quartz, to widely varying fractions of the end-members of solid solutions series. Solid solutions of geologic significance include clay minerals, zeolites, and plagioclase feldspars, which are important components in most geochemical models. 

It was found that the reaction rate could be significantly enhanced if a fluorspar addition is made to the briquette with the objective of producing a small amount of a liquid phase at the operating temperature. There is a eutectic in the Ca0-Si02-CaF2 system at a temperature of 1398K. These studies show the importance of the role of a vapour species to transport chemical potentials in a solid-solid reaction, and also the desirability of introducing a small quantity of a liquid. 

If these methods do prove inconclusive, biomedical sample analysis may provide a unique method for establishing exposure. Due to both the complex technical requirements and the strict forensic approach used it is unlikely that this information will be available in the early phases of response to such an incident. Biomedical sample analysis does however offer another method by which proof of the use of chemical agents can be provided, and thus has a potentially significant role in the overall preparation of a capability for the response to a terrorist chemical agent attack. 

The physical significance of the Gibbs-Duhem equation is that the chemical potential of one component in a solution cannot be varied independently of the chemical potentials of the other components of the solution. This relation will be further discussed and used in Chapter 3. 

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