Mixing property changes

All three quantities are for the same T, P, and physical state. Eq. (4-126) defines a partial molar property change of mixing, and Eq. (4-125) is the summability relation for these properties. Each of Eqs. (4-93) through (4-96) is an expression for an ideal solution property, and each may be combined with the defining equation for an excess property (Eq. [4-99]), yielding ... 

Property changes of mixing and excess properties find greatest application in the description of hqnid mixtures at low reduced tempera-... 

Stock of solvents were prepared so that their properties changed only little in the course of experiments. All mixed eluent compositions are given in weight %. 

The implications for films cast from mixtures of enantiomers is that diagrams similar to those obtained for phase changes (i.e., melting point, etc.) versus composition for the bulk surfactant may be obtained if a film property is plotted as a function of composition. In the case of enantiomeric mixtures, these monolayer properties should be symmetric about the racemic mixture, and may help to determine whether the associations in the racemic film are homochiral, heterochiral, or ideal. Monolayers cast from non-enantiomeric chiral surfactant mixtures normally will not exhibit this feature. In addition, a systematic study of binary films cast from a mixture of chiral and achiral surfactants may help to determine the limits for chiral discrimination in monolayers doped with an achiral diluent. However, to our knowledge, there has never been any other systematic investigation of the thermodynamic, rheological and mixing properties of chiral monolayers than those reported below from this laboratory. 

Ganguly J., Cheng W., and O Neill H. St. C. (1993). Syntheses, volume, and structural changes of garnets in the pyrope-grossular join Implications for stability and mixing properties. Amer Mineral, 78 583-593. 

The available data, therefore, suggest that by making the relevant mix design changes to compensate for the effect of entrained air on strength, the engineering properties of the concrete will be similar to a plain concrete of comparable strength. 

Whereas the fundamental residual property relation derives its usefulness from its direct relation to experimental PHT data and equations of state, the excess property formulation is useful because 1 E, HE, and y are all experimentally accessible. Activity coefficients are found from vapor—liquid equilibrium data, and T E and HE values come from mixing experiments. Property changes of mixing are defined by the equation,... 

Extensive properties of multicomponent phases (solutions) are related to the amount of material in the phase, but may not be just the sum of the properties of the constituent components. Probably the best known example of this difference is the observation that mixing 1.0 L of ethanol with 1.0 L of water at standard temperature and pressure (STP) produces 1.93 L of water-ethanol solution. We define the difference between an extensive property of the solution and the sum of the properties of its pure components as the property change of mixing for the solution ... 

In addition, for each of the major downstream processing units (FCC, hydrocracker, motor and BTX reformers), the preprocessor generates a set of feed property balance rows. It is through these rows and the corresponding feed property change activities that the unit performance can respond to changes in crude mix and distillation cutpoint as well as changes in properties or proportion of feed from other process units. 

Each material transfer activity enters a separate stream balance row with a +1 or -1 coefficient depending on whether the cutpoint change transfers material into or out of the unit. Each of these activities also enters the unit volume balance row and the feed property balance rows with appropriate sign. Feed properties for a material transfer activity are calculated by the preprocessor and represent base crude mix properties at the corresponding crude distillation cutpoint. 

In each of these equations there appears to the right of the equals sign a difference that is expressed in general as Af - XfM,. We call this quantity a property change of mixing and give it the symbol AM Thus by definition,... 

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