Determination of Parameters for Mixtures

By double linear interpolation, where the first interpolation is performed in the table, we get , 0.02,  

The low value for the compressibility factor indicates that butane is a liquid. Now solving for volume  

The compressibility charts and the Redlich-Kwong equation give similar values for liquid butane at 50 bar and 60°C. 

Most chemical and biological engineering processes include systems in which the working fluid is a mixture of two or more components. In Chapter 6, we will learn how to carefully approach the thermodynamic properties of mixtures however, it is useful to introduce the approach to apply equations of state to mixtures while intermolecular interactions are fresh in our mind. 

When approaching mixtures, it is useful to consider all the possible types of interactions between the molecules in the mixture. These include hke interactions between two molecules of the same species and unlike interactions between molecules of different species. For example, a binary mixture of species 1 and 2 can have three types of interactions hke interactions between 1 and 1, hke interactions between 2 and 2, and unlike interactions between 1 and 2. Similarly, a ternary mixture can have six types of interactions, a quaternary mixture 10 types, and so on. As we quickly can recognize, virtually an unlimited combination of mixtures is possible. Mixtures can vary not only by the 

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