Book contents
- Frontmatter
- Contents
- Preface
- Notation
- 1 Introduction
- 2 Temperature, heat, work, energy, and enthalpy
- 3 The second law of thermodynamics: the entropy function
- 4 Gibbs and Helmholtz energy functions and open systems
- 5 Conditions of equilibrium and stability: the phase rule
- 6 Partial molar quantities
- 7 Ideal gases and real gases
- 8 Liquids and solids: reference and standard states
- 9 Thermochemistry
- 10 Phase equilibrium
- 11 Chemical equilibrium
- 12 Equilibria in electrochemical systems
- 13 Surface effects
- 14 Equilibrium conditions in the presence of an external field
- 15 The third law of thermodynamics
- Appendices
- Cited references and selected bibliography
- Subject index
14 - Equilibrium conditions in the presence of an external field
Published online by Cambridge University Press: 28 October 2009
- Frontmatter
- Contents
- Preface
- Notation
- 1 Introduction
- 2 Temperature, heat, work, energy, and enthalpy
- 3 The second law of thermodynamics: the entropy function
- 4 Gibbs and Helmholtz energy functions and open systems
- 5 Conditions of equilibrium and stability: the phase rule
- 6 Partial molar quantities
- 7 Ideal gases and real gases
- 8 Liquids and solids: reference and standard states
- 9 Thermochemistry
- 10 Phase equilibrium
- 11 Chemical equilibrium
- 12 Equilibria in electrochemical systems
- 13 Surface effects
- 14 Equilibrium conditions in the presence of an external field
- 15 The third law of thermodynamics
- Appendices
- Cited references and selected bibliography
- Subject index
Summary
In all of the studies of thermodynamic equilibrium that have been presented in the previous chapters, we have neglected the effects of an external field on the equilibrium properties of a system. This has been justified because the field may be present only in specific cases, the effect of the field may be negligible, or the position of the system in the field may be unchanged. The conditions of equilibrium in the presence of a gravitational or centrifugal field, an electrostatic field, and a magnetic field are developed in this chapter.
A distinction must be made between gravitational effects for which the presence of material in the field does not change the intensity of the field, and the electrostatic and magnetic effects for which the presence of material within the field does alter the intensity. A complete treatment of electrostatic and magnetic effects would require a discussion of electromagnetic theory and the use of Maxwell's equations. However, we wish only to illustrate the thermodynamic effects of electric and magnetic fields. We therefore accept the results of a complete treatment and apply the results to simple systems.
THE GRAVITATIONAL AND CENTRIFUGAL FIELD
The gravitational and centrifugal potential
The gravitational field of the Earth is characterized by a potential, Φ, that has a definite value at each point in the field.
- Type
- Chapter
- Information
- Thermodynamics of Chemical Systems , pp. 376 - 398Publisher: Cambridge University PressPrint publication year: 1990