Which occurs when two fluorine atoms react to produce a fluorine molecule?
(1) energy is absorbed as a bond is broken.
(2) energy is absorbed as a bond is formed.
(3) energy is released as a bond is broken.
(4) energy is released as a bond is formed.

The answer is 4. When atoms mix to create a compound, energy is continuously set off, and the compound has a lesser total energy. When a chemical reaction happens, molecular bonds are shattered and other bonds are made to create unalike molecules. For instance, the bonds of two water molecules are shattered to make hydrogen and oxygen.

Spontaneity tell us the direction of the reaction, but not how fast it goes. gibbs free energy brings together enthalpy, entropy and temperature in one easy formula. g = h - ts. and, finally the sign of delta g is always negative for a spontaneous reaction.