Review some common exothemic reactions and note have a negative heat of reaction and are spontaneous reactions . Present a few endothermic reactions, specifically the melting of ice which has a positive heat of reaction. Demonstrate and discuss the direction of heat flow in that system. Elicit that the flow transfers heat energy from hot to cold. Determine the energy is transferred from the surroundings to the system. State that the evolution of heat energy is not sufficient to determine spontaneity. Discuss the first law of thermodynamics and how energy transferred as heat proceeds from higher concentration to a more dispersed system. Quantify this function of dispersed heat energy as entropy by being able to give it a number.