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5: Single Component Phase Equilibrium

  • Page ID
    477388
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    • 5.1: Gibbs Energies and Phase Diagrams
      Gibbs energy is a continuous function as a function of temperature. The derivative, however, is discontinuous during phase changes.
    • 5.2: Chemical Potential and Fugacity
    • 5.3: The Gibbs-Duhem Equation
      The Gibbs-Duhem equation relates how the chemical potential can change for a given composition while the system maintains equilibrium. So for a binary system, consisting of components A and B (the two most often studied compounds in all of chemistry)
    • 5.4: Criterion for Phase Equilibrium
      The thermodynamic criterion for phase equilibrium is simple. It is based upon the chemical potentials of the components in a system. For simplicity, consider a system with only one component. For the overall system to be in equilibrium, the chemical potential of the compound in each phase present must be the same.
    • 5.5: Phase Diagrams for Pure Substances
      This page explains how to interpret the phase diagrams for simple pure substances - including a look at the special cases of the phase diagrams of water and carbon dioxide.
    • 5.6: Gibbs Phase Rule
      In chapter 1, we have already seen that the number of independent variables required to describe an ideal gas is two. This number was derived by counting the total number of variables (3:P,V¯,T), and reduce it by one because the ideal gas law constrains the value of one of them, once the other two are fixed.
    • 5.7: The Clapeyron Equation
      Based on the thermodynamic criterion for equilibrium, it is possible to draw some conclusions about the state variables p and T and how they are related along phase boundaries. This results in the Clapeyron equation.
    • 5.8: The Clausius-Clapeyron Equation
      The Clapeyron equation can be developed further for phase equilibria involving the gas phase as one of the phases. This is the case for either sublimation (solid → gas) or vaporization (liquid → gas).


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