The Fundamental Thermodynamic Criterion of Phase and Chemical Equilibrium

1 THE FUNDAMENTAL THERMODYNAMIC CRITERION OF PHASE AND CHEMICAL EQUILIBRIUM 

Here the only work term is that of driving back the piston. A differential change in any system at equilibrium is a reversible process for a reversible batch process, the second law shows us that 

But we have restricted the process to constant temperature and pressure, so the two terms on the right of Eq. 4.5 are zero, and we can say that for any reversible equilibrium change at constant T and P 

Physical and Chemical Equilibrium for Chemical Engineers, Second Edition. Noel de Nevers. 2012 John Wiley Sons, Inc. Published 2012 by John Wiley Sons, Inc. 

Contents of the container may be anything, any number of phases and/or chemical species 

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