What is the difference between a molecule and a compound?

-A molecule consists of two or more atoms that are chemically joined together

Example of molecule: H2 (molecular hydrogen); it has two hydrogen atoms

-A compound IS a molecule that consists of two different types of elements

Example of compound: H2O (water); it has two hydrogen atoms and one oxygen atom

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.