The change in this quantity with an increase in surface area is given by Stefan's formula and is equal to surface tension for isotropic materials. Because this quantity is defined for isobaric systems, systems with varying pressure but constant volume use a quantity named after (*) Helmholtz instead. The standard change in 
The change in this quantity with an increase in surface area is given by Stefan's formula and is equal to surface tension for isotropic materials. Because this quantity is defined for isobaric systems, systems with varying pressure but constant volume use a quantity named after (*) Helmholtz instead. The standard change in this quantity over the course of a reaction is equal to negative RT times the natural log of the equilibrium constant, and is also equal to enthalpy change minus temperature times entropy change or delta H minus T delta S. Minimized at chemical equilibrium, for 10 points, this is what thermodynamic state function which determines the spontaneity of a reaction, symbolized G?
The change in this quantity with an increase in surface area is given by Stefan's formula and is equal to surface tension for isotropic materials.
{Gibbs} free {energy} [accept {Gibbs function}; accept {free energy} before "isobaric" and prompt afterwards; prompt on {G} before read]