Chemical thermodynamics

Chemical Thermodynamics

Chemical thermodynamics is the study of the interrelation of heat and work with chemical reactions or with physical changes of state within the confines of the laws of thermodynamics. Chemical thermodynamics involves not only laboratory measurements of various thermodynamic properties, but also the application of mathematical methods to te study of chemical questions and the spontaneity of processes. the structure of chemical thermodynamics is based on the first two laws of thermodynamics. starting from the first and second laws of thermodynamics, four equations called the "fundamental equations of Gibbs". From these four, a multitude of equations, relating the thermodynamic properties of the thermodynamic system. This outline the mathematical framework of chemical thermodynamics.

History

In 1865, the German physicist Rudolf Clausius, in his Mechanical Theory of Heat, suggested that the principals of thermochemistry, e.g. the heat evolved in combustion reactions, could be applied to the principles of thermodynamics. Building on the work of Clausius, between the years1873-76 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.

During the early 20th century, two major publications successfully applied the principles developed by Gibbs to chemical processes and thus established te 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 free energy in the English speaking world. The second was the 1933 book Modern Thermodynamics by the methods of Willard Gibbs written by EA. Guggenheim. In this manner, Lewis, Randall, and Guggenheim are considered as then founders of modern chemical thermodynamics because of the major contribution of these two books in unifying the application of thermodynamics to chemistry.

Overview

The primary objective of chemical thermodynamics is the establishment of a criterion for the determination of the feasibility or spontaneity of a given transformation. In this manner, chemical thermodynamics is typically used to predict the energy  exchanges that occur in the following processes:

1. Chemical reactions 
2. Phase changes 
3. The formation of solution.

The following states functions are of primary concern in chemical thermodynamics:

• Internal energy (U)
• Enthalpy (H)
• Entropy (S)
• Gibbs free energy (G)Most identities in chemical thermodynamics arise from the application of the first and second laws of thermodynamics, particularly the law of conservation of energy, to these states functions

The three laws of thermodynamics:

1. The energy of the universe is constant.
2. In any spontaneous process, there is always an increase in entropy of the universe
3. The entropy of a perfect crystal(well ordered) at 0 Kelvin is zero