Compounds with weak bonds react quickly. The heat of reaction is always positive for an exothermic reaction. The Law of Conservation of energy says the energy in the universe is constant. A spontaneous reaction is one that produces an explosion 8. Entropy, S, increases when disorder increases.
Free energy is the energy available from a reaction that can be used for other purposes.
Activation energies are high for slow reactions. Reactions occur more slowly if the temperature is raised. A reaction with an activation energy of 35000 calories is low and the reaction is fast. Entropy is always increasing. It is not governed by a conservation law.