Reactions are spontaneous if the change in this quantity is negative.
The molar version of this quantity is also known as the chemical potential. This quantity is proportional to the natural log of the equilibrium constant. It differs from a similarly named concept in that it is equal to (*) enthalpy, not internal energy, minus the product of temperature and entropy. Reactions are spontaneous if the change in this quantity is negative. For 10 points, give this type of free energy named after an American scientist, which is denoted G.
The molar version of this quantity is also known as the chemical potential.
{Gibbs} free energy [prompt on {G}]