3.1 Common feature of spontaneous change 3.2 The second law of thermodynamics 3.3 Carnot cycle and Carnot principle 3.4 Definition of entropy 3.5 Clausius inequality ; principle of increase of entropy 3.6 Calculate the change of entropy 3.7 Statistical view of entropy 3.9 Direction of change and conditions in equilibrium 3.10 Calculate of G 3.11 Relations of thermodynamic functions 3.12 Clapeyron equation 3.13 The third law and conventional entropy 3.8 Helmholtz function and Gibbs function