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  • Scientific Units, Constants, Conventions

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    There are seven base units within the International System of Units (SI system), as shown in Table 1.1 for quick reference. Except for luminous intensity, all of the quantities are used extensively in this text. Among the base units is electric current, I, which is critical for the examination of electrochemical systems. Electric current is measured in amperes…

  • Importance of Electrochemical Systems

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    Electrochemical systems are not only essential for our society but are also common in everyday life. Imagine a world without batteries to power your personal electronic devices. How would travel change without low-cost aluminum that is essential for aircraft? What if corrosion of the steel in bridges, the hulls of ships, superstructures of buildings, and…

  • Characteristics of Electrochemical Reactions

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    Electrochemical reactions are reactions where electrons are transferred through a conductor from the species being oxidized to that being reduced. Most of the unique and important properties of electrochemical reactions are the result of the way that these electrons are transferred. These characteristics include the following: This textbook will help you to understand and to use…

  • Electrochemical Cells

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    Electrochemical cells, such as the cell illustrated in Figure 1.1, lie at the heart of electrochemical systems. A typical electrochemical cell consists of two electrodes: an anode where oxidation occurs and a cathode where reduction takes place. Electrons move through an external circuit via an electronic conductor that connects the anode and cathode. The liquid solution that is between the…

  • Practice Problems

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    P19.1. a. A gas-phase A+B system solvates A + B  AB with Ka = 0.5 at 298.15 K. Calculate the compressibility factor, apparent fugacity coefficients, and the true vapor phase mole fractions in a mixture at 298.15 K and 2 bar when the apparent concentration is yA = 0.45 using ideal chemical theory. b. A liquid-phase A+B system solvates A + B  AB with Ka = 0.7 at 298.15 K. Calculate the true…

  • Summary

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    A simple way of remembering the qualitative conclusions of this analysis can be derived by considering the behavior of the fugacity coefficient. One can easily demonstrate that the fugacity coefficient of the monomeric species is insensitive to the extent of association if it is expressed on the basis of the true number of moles in…

  • Fitting the Constants for an Associating Equation of State

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    To this point in the discussion, we have assumed that the constants needed for a fluid are available. However, association models add complexity in the sense that two association parameters must be characterized in addition to the usual size (b), energy (a or ε), and shape (k, m, q, or c). One simple approach is to assign standardized values…

  • Statistical Associating Fluid Theory (The SAFT Model)

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    Shortly after Wertheim’s work appeared, Chapman et al. formulated an equation of state that incorporated the bonding contribution and complexation as well as the disperse repulsive and attractive terms. Their perspective was to treat any solution in the conventional way as a fluid of independent spheres, then to add the bonding contribution required to assemble…

  • Wertheim’s Theory of Polymerization

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    Now that we have an accounting for the thermodynamics of bond formation, it is natural to wonder what happens to the thermodynamics as the bond energy approaches infinity. This would be a natural limit for covalent bond formation. Having a theoretical basis for nonspherical molecules would be a big step forward, considering that all theories…

  • The Chemical Contribution to the Fugacity Coefficient and Compressibility Factor

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    The solution to phase equilibrium problems can be achieved in the manner of Chapter 15 (Eqn 15.20), where Eqns. 19.1 and 19.2 describe the enhanced equation of state. Eqns. 19.75–19.77 completely characterize the temperature, density, and composition dependence of the chemical contribution to Helmholtz energy. The Zchem contribution is implied, but requires differentiation as in RT·Zchem = –V∂(A – Aig)/∂V. Similarly, the fugacity coefficient is implicitly determined through differentiation.…