Editing Chemical thermodynamics (section)

==History==
[[File:Willard Gibbs.jpg|upright|thumb|[[J. Willard Gibbs]] - founder of ''chemical thermodynamics'']]
In 1865, the German physicist [[Rudolf Clausius]], in his ''Mechanical Theory of Heat'', suggested that the principles of [[thermochemistry]], e.g. the [[heat]] evolved in [[Combustion|combustion reactions]], could be applied to the principles of [[thermodynamics]].<ref>Clausius, R. (1865). ''The Mechanical Theory of Heat – with its Applications to the Steam Engine and to Physical Properties of Bodies.'' London: John van Voorst, 1 Paternoster Row. MDCCCLXVII.</ref>  Building on the work of Clausius, between the years 1873-76 the American mathematical physicist [[Willard Gibbs]] published a series of three papers, the most famous one being the paper ''[[On the Equilibrium of Heterogeneous Substances]]''.  In these papers, Gibbs showed how the first two laws of thermodynamics could be measured graphically and mathematically to determine both the [[thermodynamic equilibrium]] of chemical reactions as well as their tendencies to occur or proceed.  Gibbs’ collection of papers provided the first unified body of thermodynamic theorems from the principles developed by others, such as Clausius and [[Nicolas Léonard Sadi Carnot|Sadi Carnot]].

During the early 20th century, two major publications successfully applied the principles developed by Gibbs to chemical processes and thus established the foundation of the science of chemical thermodynamics. The first was the 1923 textbook ''Thermodynamics and the Free Energy of Chemical Substances'' by [[Gilbert N. Lewis]] and [[Merle Randall]]. This book was responsible for supplanting the [[chemical affinity]] with the term [[thermodynamic free energy|free energy]] in the English-speaking world. The second was the 1933 book ''Modern Thermodynamics by the methods of Willard Gibbs'' written by [[E. A. Guggenheim]]. In this manner, Lewis, Randall, and Guggenheim are considered as the founders of modern chemical thermodynamics because of the major contribution of these two books in unifying the application of [[thermodynamics]] to [[chemistry]].<ref name="Book1" />