Contents

On the Equilibrium of Heterogeneous Substances

Paper by Josiah Willard Gibbs

Thermodynamics
The classical Carnot heat engine
Branches Classical Statistical Chemical Quantum thermodynamics Equilibrium / Non-equilibrium
Laws Zeroth First Second Third
Systems Closed system Open system Isolated system State Equation of state Ideal gas Real gas State of matter Phase (matter) Equilibrium Control volume Instruments Processes Isobaric Isochoric Isothermal Adiabatic Isentropic Isenthalpic Quasistatic Polytropic Free expansion Reversibility Irreversibility Endoreversibility Cycles Heat engines Heat pumps Thermal efficiency
System properties Note: Conjugate variablesinitalics Property diagrams Intensive and extensive properties Process functions Work Heat Functions of state Temperature / Entropy (introduction) Pressure / Volume Chemical potential / Particle number Vapor quality Reduced properties
Material properties Property databases Specific heat capacity  ${\displaystyle c=}$ ${\displaystyle T}$ ${\displaystyle \partial S}$ ${\displaystyle N}$ ${\displaystyle \partial T}$ Compressibility  ${\displaystyle \beta =-}$ ${\displaystyle 1}$ ${\displaystyle \partial V}$ ${\displaystyle V}$ ${\displaystyle \partial p}$ Thermal expansion  ${\displaystyle \alpha =}$ ${\displaystyle 1}$ ${\displaystyle \partial V}$ ${\displaystyle V}$ ${\displaystyle \partial T}$
Equations Carnot's theorem Clausius theorem Fundamental relation Ideal gas law Maxwell relations Onsager reciprocal relations Bridgman's equations Table of thermodynamic equations
Potentials Free energy Free entropy Internal energy ${\displaystyle U(S,V)}$ Enthalpy ${\displaystyle H(S,p)=U+pV}$ Helmholtz free energy ${\displaystyle A(T,V)=U-TS}$ Gibbs free energy ${\displaystyle G(T,p)=H-TS}$
History Culture History General Entropy Gas laws "Perpetual motion" machines Philosophy Entropy and time Entropy and life Brownian ratchet Maxwell's demon Heat death paradox Loschmidt's paradox Synergetics Theories Caloric theory Vis viva ("living force") Mechanical equivalent of heat Motive power Key publications An Experimental Enquiry Concerning ... Heat On the Equilibrium of Heterogeneous Substances Reflections on the Motive Power of Fire Timelines Thermodynamics Heat engines Art Education Maxwell's thermodynamic surface Entropy as energy dispersal
Scientists Bernoulli Boltzmann Bridgman Carathéodory Carnot Clapeyron Clausius de Donder Duhem Gibbs von Helmholtz Joule Kelvin Lewis Massieu Maxwell von Mayer Nernst Onsager Planck Rankine Smeaton Stahl Tait Thompson van der Waals Waterston
Other Nucleation Self-assembly Self-organization Order and disorder
Category
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In the history of thermodynamics, "On the Equilibrium of Heterogeneous Substances" is a 300-page paper written by American chemical physicist Willard Gibbs. It is one of the founding papers in thermodynamics, along with German physicist Hermann von Helmholtz's 1882 paper "Thermodynamik chemischer Vorgänge." Together they form the foundation of chemical thermodynamics as well as a large part of physical chemistry.^[1][2]

Gibbs's paper marked the beginning of chemical thermodynamics by integrating chemical, physical, electrical, and electromagnetic phenomena into a coherent system. It introduced concepts such as chemical potential, phase rule, and more, which form the basis for modern physical chemistry. American writer Bill Bryson describes Gibbs's paper as "the Principia of thermodynamics".^[3]

"On the Equilibrium of Heterogeneous Substances", was originally published in a relatively obscure American journal, the Transactions of the Connecticut Academy of Arts and Sciences, in several parts, during the years 1875 to 1878 (although most cite "1876" as the key year).^[4][5] It remained largely unknown until translated into German by Wilhelm Ostwald and into French by Henry Louis Le Châtelier.

Overview[edit]

Gibbs first contributed to mathematical physics with two papers published in 1873 in the Transactions of the Connecticut Academy of Arts and Sciences on "Graphical Methods in the Thermodynamics of Fluids," and "Method of Geometrical Representation of the Thermodynamic Properties of Substances by means of Surfaces." His subsequent and most important publication was "On the Equilibrium of Heterogeneous Substances" (in two parts, 1876 and 1878). In this monumental, densely woven, 300-page treatise, the first law of thermodynamics, the second law of thermodynamics, the fundamental thermodynamic relation, are applied to the predication and quantification of thermodynamic reaction tendencies in any thermodynamic system in a visual, three-dimensional graphical language of Lagrangian mechanics and phase transitions, among others.^[6][7] As stated by Le Chatelier, it "founded a new department of chemical science that is becoming comparable in importance to that created by [Antoine] Lavoisier." This work was translated into German by Ostwald (who styled its author the "founder of chemical energetics") in 1891 and into French by Le Châtelier in 1899.^[8]

Gibbs's Equilibrium paper is considered one of the greatest achievements in physical science in the 19th century and one of the foundations of the science of physical chemistry.^[2] In these papers Gibbs applied thermodynamics to the interpretation of physicochemical phenomena and showed the explanation and interrelationship of what had been known only as isolated, inexplicable facts.

Gibbs' papers on heterogeneous equilibria included:

• Some chemical potential concepts
• Some free energy concepts
• AGibbsian ensemble ideal (basis of the statistical mechanics field)
• the phase rule

References[edit]

External links[edit]

Wikisource has the text of the 1911 Encyclopædia Britannica article "Gibbs, Josiah Willard".

Wikisource has original text related to this article:

On the Equilibrium of Heterogeneous Substances

• At the Internet Archive, Part 1 and Part 2 in various file formats.