Summary:
- Free energy is energy that is available to do work.
- The symbol for free energy is , in honor of American scientist Josiah Gibbs (1839-1903), who made many contributions to thermodynamics.
- The determining factors for spontaneity of a reaction are the enthalpy and entropy changes that occur for the system.
- A spontaneous reaction is one that releases free energy, and so the sign of must be negative.
- There are four different general outcomes for and these are outlined in the Table below.