Lately I've been struggling with the idea of enthalpy and what it means conceptually, especially in its use in Gibb's free energy. There is nothing in the definition of change in enthalpy that would connect logically to spontaneity or free energy. After thinking about it for a couple days, here are my ideas about spontaneity. I expect some or even all of them to be wrong, so it would help me very much if someone could correct my mistakes or show me where I managed to get things right. 1. Enthalpy is just a way of measuring the energy released by something at constant pressure. We could measure it using the change in internal energy at constant volume, but in that case pressure would not be constant. 2. Things tend to become disordered because disorder is statistically favored. Things also tend to want to lose potential energy. It takes a certain amount of the latter tendency to overcome the former tendency and vice versa. 3. [tex]\Delta G=\Delta H - T\Delta S[/tex] is just a way of apply (2) to systems of gases, most of the time involving chemical reactions. 4. [tex]\Delta G=-nF\Delta E[/tex] is an application of (2) to electrochemistry. 5. Any spontaneous changes where entropy decreases is accompanied and balanced out by the conversion of potential energy into other forms.