CHEM 107 Lecture Notes - Lecture 18: Chemical Thermodynamics

• School: Texas A&M University
• Department: Chemistry
• Course: CHEM 107
• Professor: Hughbanks Timothy

Document Summary

Delta s of the universe is greater than zero for a spontaneous change. Free energy is g=h-ts: g is a state funcion and predicts spontaneity, this is the central equaion in chemical thermodynamics. A spontaneous reacion has delta g less than zero: delta g also tells the max amount of energy which can be produced and used to do work. If delta h is less than zero it is exothermic and favors spontaneity. If delta s is greater than zero, entropy increases and it favors spontaneity. If both delta h and delta s are greater than zero then it is only spontaneous at suiciently high temperatures. If both delta h and delta s are less than zero then it is only spontaneous at suiciently low temperatures. All phase change are determined by delta g: phases are in equilibrium when delta g = zero, p-t phase diagrams tell what phrases are stable at various values of t and p.