版权所有：华东理工大学物理化学教研室 11 The system has three constituents but only two components (C = 2). The number of components: C = 2 At the equilibrium 3 ↔ CaO(s) (s)CaCO + 2 (g)CO Phase 1 Phase 2 Phase 3 Cst 1 Cst 2 Cst 3 Answer: Example
版权所有：华东理工大学物理化学教研室 11 The system has three constituents but only two components (C = 2). The number of components: C = 2 At the equilibrium 3 ↔ CaO(s) (s)CaCO + 2 (g)CO Phase 1 Phase 2 Phase 3 Cst 1 Cst 2 Cst 3 Answer: Example
版权所有：华东理工大学物理化学教研室 12 8.1 Definitions 3). Degrees of freedom, F Degrees of freedom ,or the variance of a system, F, is the number of intensive variables that can be changed independently without disturbing the number of phases in equilibrium. In a single-component, single-phase system (C = 1, P = 1), p and T may be changed independently without changing the number of phases, so F = 2. We say that such a system is bivariant, or that it has two degrees of freedom
版权所有：华东理工大学物理化学教研室 12 8.1 Definitions 3). Degrees of freedom, F Degrees of freedom ,or the variance of a system, F, is the number of intensive variables that can be changed independently without disturbing the number of phases in equilibrium. In a single-component, single-phase system (C = 1, P = 1), p and T may be changed independently without changing the number of phases, so F = 2. We say that such a system is bivariant, or that it has two degrees of freedom
版权所有：华东理工大学物理化学教研室 13 8.1 Definitions 3). Degrees of freedom, F If two phases are in equilibrium in a singlecomponent system(C = 1, P = 2), T (or p) can be changed at will, but the change in T (or p) demands an accompanying change in p (or T) to preserve the number of phases in equilibrium. That is, the variance of the system has fallen to F=1
版权所有：华东理工大学物理化学教研室 13 8.1 Definitions 3). Degrees of freedom, F If two phases are in equilibrium in a singlecomponent system(C = 1, P = 2), T (or p) can be changed at will, but the change in T (or p) demands an accompanying change in p (or T) to preserve the number of phases in equilibrium. That is, the variance of the system has fallen to F=1
版权所有：华东理工大学物理化学教研室 14 Phases, components, and degrees of freedom 8.1 Definitions 8.2 The phase rule Two-component systems 8.3 Vapour pressure diagrams 8.4 Temperature-composition diagrams 8.5 Liquid-liquid phase diagrams 8.6 Liquid-solid phase diagrams 8.7 Ultrapurity and controlled impurity 8. Phase diagrams
版权所有：华东理工大学物理化学教研室 14 Phases, components, and degrees of freedom 8.1 Definitions 8.2 The phase rule Two-component systems 8.3 Vapour pressure diagrams 8.4 Temperature-composition diagrams 8.5 Liquid-liquid phase diagrams 8.6 Liquid-solid phase diagrams 8.7 Ultrapurity and controlled impurity 8. Phase diagrams
版权所有：华东理工大学物理化学教研室 15 8.2 The phase rule The phase rule is a general relation between the variance, F, the number of components, C, and the number of phases at equilibrium, P, for a system of any composition: = − PCF + 2
版权所有：华东理工大学物理化学教研室 15 8.2 The phase rule The phase rule is a general relation between the variance, F, the number of components, C, and the number of phases at equilibrium, P, for a system of any composition: = − PCF + 2