Properties of the Gibbs energy

The Gibbs energy is related to enthalpy and entropy through G = H - TS. For an infinitesimal change in the system 

Thus in the absence of non-expansion work for a closed system, the following important equation 

Equation (1.70) applies to each substance in a reaction and a change in the standard Gibbs energy of a reaction (p is nowp°= 1 bar) going from Tj to Tf is given by 

Ar S 0 is not necessarily positive and the Gibbs energy of a reaction may increase with temperature. 

The pressure derivative of the Gibbs energy (eq. 1.68) at constant temperature is V  

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The chemical potential of component i is equal to the partial molar property of the Gibbs energy. 

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