09.05 - Fugacity and Fugacity Coefficient

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What is fugacity? (10min) (learncheme.com) Defines fugacity in terms of Gibbs Energy and describes the need for defining this new property as a generalization of how pressure affects ideal gases.
Comprehension Questions
1. The phases in this video start with concentrations 0.0007kg/L and 1.0 kg/L, when not at equilibrium. What are the equilibrium concentrations?
2. Why is concentration an unreliable indicator for the direction of mass transfer?
3. Name two indicators for the direction of mass transfer that are superior to concentration.  

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In a contest for "the most hated word in Chemical Engineering," fugacity won by a landslide. This video (15min, uakron.edu) reviews how the term was developed and why it's not really as bad as all that. In fact, it's a nice word that sets the stage for all of phase and reaction equilibrium with a straightforward extension of the same conceptual basis to mixtures. On second thought, perhaps the power of that conceptual basis and all that it implies is what really intimidates new students. Many perspectives have been offered to help overcome the frustration that students feel toward fugacity. If you like a comic book perspective, even that is available.

Comprehension Questions:

1.What is the fugacity of a vapor phase component in a mixture according to Raoult's law?
2.What is the fugacity of a liquid phase component in a mixture according to Raoult's law?
3. What word is modern usage is closely related to the latin root "fuga-"?
4. Water is in VLE at 0.7 bars in a fixed volume vessel. Five cm3 of air are injected into the vessel and the temperature is allowed to return to its original value. Does the water in the vapor phase increase, decrease, or remain the same? (Learncheme.com, 2min) (Hint: you may assume that air does not dissolve in the liquid water and the pressure is sufficiently low that the vapor can be assumed to behave as an ideal gas.)

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