Pure liquid compound

A compilation of data of some 2200 pure liquid compounds has been prepared by Jasper, J. Phys. Chem. Reference Data 1 841 (1972). 

Example 1 Vapor Pressure and Molecular Interactions in the Pure Liquid Compound Example 2 Air-Solvent Partitioning Examples of Adsorption from the Gas Phase Example 3 Air-Solid Surface Partitioning... 

If we consider, for example, compound i in a liquid mixture, e.g., in organic or in aqueous solution (subscript t see Fig. 3.9[Pg.78]

Figure 3.9 Conceptualization of the fugacity of a compound i (a) in an it/ea/ gas (h) in a pure liquid compound i (c) in an Wen/ liquid mixture and (d) in a nonideal liquid mixture (e.g., in aqueous solution). Note that in (b), (c), and (d), the gas and liquid phases are in equilibrium with one another.

But let us now inspect the Yu values for the various chemicals given in Table 3.2. As we would probably have expected intuitively from our discussions in Section 3.2, Yu values close to 1 are found in those cases in which molecular interactions in the solution are nearly the same as in the pure liquid compound. For example, when the intermolecular interactions in a pure liquid are dominated by vdW interactions, and when solutions also exhibit only vdW interactions between the solute and solvent and between the solvent molecules themselves, we have Yu values close to 1. Examples include solutions of nonpolar and monopolar compounds in an apolar solvent (e.g., n-hexane, benzene, and diethylether in hexadecane), as well as solutions of nonpolar solutes in monopolar solvents (e.g., n-hexane in chloroform). In contrast, if we consider situations in which strong polar interactions are involved between the solute... 

Octanol-water partition constant and aqueous solubility of the pure liquid compound l°g - iow = -a- logCf + b 7... 

Air-solid surface partition constant and vapor pressure of the pure liquid compound log ATi as = a logpiL. + b 11... 

Fig. 3.4 shows that when plotting the air-pure liquid compound partition constants of a large number of chemicals versus their dispersive vdW parameters, the apolar and monopolar compounds fall more or less on one line, while the bipolar compounds do not show this behavior. Explain these findings. For which kind of bulk liquids (give examples) would you expect that in a similar plot, all compounds (including the bipolar ones) should fit one line ... 

What are the advantages and disadvantages of choosing the pure liquid compound as reference state ... 

Substituting ptlxiL by p (the saturation vapor pressure of the pure liquid compound, since =1) and by realizing that in this case, A12G, (see Eq. 3-46) is simply given by G (the excess free energy of the compound in the gas phase see examples given in Table 3.2) we may rewrite Eq. 4-3 as ... 

So far, we have used the pure liquid compound as reference state for describing the thermodynamics of transfer processes between different media (Chapter 3). When treating reactions of several different chemical species in one medium (e.g., water) it is, however, much more convenient to use the infinite dilution state in that medium as the reference state for the solutes. Hence, for acid-base reactions in aqueous solutions, in analogy to Eq. 3-34, we may express the chemical potential of the solute i as ... 

In this case, AfG,° values are available only for the pure liquid compounds (Dean, 1985). Also known are the aqueous solubilities of the two compounds. Since for the solvent H20 the reference state is the pure liquid, you may directly use AfG 0(f). For NB and An, however, you need to calculate AfG,°(aq), that is, the standard free energy of formation in aqueous solution at a concentration of 1 M. From Chapters 3 and 5 you recall that transferring a compound from its pure liquid to water is given by the term RJln x,wyiw. In this case, you want x/w at 1 M. Therefore, you obtain ... 

Jasper, J. J., The Surface Tension of Pure Liquid Compounds. J. Phys. Chem. Ref. Data, 1972 1, 841-1009. 

Although it is not really needed at this point, we introduce the concept of activity coefficients, which are very common for chemical engineers, but much less for theoretical and computational chemists. In the standard definition, the activity coefficients make reference to the pure liquid compound, i, at the same temperature and pressure. Hence, the activity coefficient yt of species i is defined by... 

When choosing the standard state for liquid or solid solutions we distinguish between the solute and the solvent. For the component which predominates in the solution i. e. for the solvent, the state of pure liquid compound at the temperature of the system and the pressure of 1 atm. is almost generally chosen. 

J.J. Jasper. The Surface Tension of Pure Liquid Compounds, J. Phys. Chem. Ref Data 1 (1972) 841-1010. (Extensive tabulations, mostly as a function of temperature. Linearized plots are given, valid for at least part of the y(T) range between 0 and 100 C, see fig. 1.27.)... 

Volume percent is commonly used to specify the concentration of a solution prepared by diluting a pure liquid compound with another liquid. For example, a 5% aqueous solution of methanol usually describes a solution prepared by diluting 5.0 mL of pure methanol with enough water to give 100 mL. 

A pure liquid compound with an overpowering vinegar odor is 40.0% C, 6.67% H, and 53.3% O. Its molecular mass is 60.0. What is its empirical formula What is its molecular formula ... 

Some of the species that take part in these electrode reactions are pure solid compounds and pure liquid compounds. In dilute aqueous solutions, water can be treated as a pure liquid. For pure solid compounds or pure liquid compounds, activities are constant and their values are considered to be unity. The activities of gases are usually taken as their partial pressures and the activities (a) of solutes... 

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