Spontaneous: is the direction of the reaction that would take a reaction mixture closer to a state of chemical equilibrium: most are exothermic but some are endothermic, enthalpy is not the only reason for spontaneity. Spontaneous process: is a process that occurs without any outside interventions. The fundamental goal of thermodynamics is to predict spontaneity. 17. 2 - entropy and the second law of thermodynamics: Entropy (s): is the measure of the lack of order due to the dispersal of energy (j) and matter per unit temperature (k). Entropy is a state function, which means that it depends on where a reaction begins and finishes. The second law of thermodynamics: is any spontaneous process that causes an increase in the entropy of the universe. The third law of thermodynamics: there is no disorder in a perfect crystal at 0 k, or s = 0. The reference point for entropy is provided by this law.