The Foundations of Thermodynamics

Fig. 6.1), who helped to lay the foundations of thermodynamics, believed that work resulted from the flow of caloric, just as the flow of water turns a water wheel. Some of Carnot s conclusions survive, but we now know that there is no such substance as caloric. About 25 years after Carnot proposed his ideas in the early nineteenth century, the English physicist James Joule showed that both heat and work are forms of energy (Fig. 6.2). 

In contrast to mechanics, electromagnetic field theory, or relativity, where the names of Newton, Maxwell, and Einstein stand out uniquely, the foundations of thermodynamics originated from the thinking of over half a dozen individuals Carnot, Mayer, Joule, Helmholtz, Rankine, Kelvin, and Clausius [1]. Each person provided cmcial steps that led to the grand synthesis of the two classic laws of thermodynamics. 

In carrying out the procedure for determining mechanisms that is presented here, one obtains a set of independent chemical reactions among the terminal species in addition to the set of reaction mechanisms. This set of reactions furnishes a fundamental basis for determination of the components to be employed in Gibbs phase rule, which forms the foundation of thermodynamic equilibrium theory. This is possible because the specification of possible elementary steps to be employed in a system presents a unique a priori resolution of the number of components in the Gibbs sense. 

These four laws form the foundation of thermodynamics and have never been known to be violated. These laws govern the physical behaviors that we observe every day. These laws can also be seen as goals toward which we must strive in order to make our technological world more thermodynamically efficient and more sustainable for future generations. 

The power of thermodynamics lies in its generality It rests on no particnlar model of the structure of matter. In fact, if the entire atomic theory of matter were to be found invalid and discarded (a very unlikely event ), the foundations of thermodynamics would remain nnshaken. Nonetheless, thermodynamics has some important limitations. Thermodynamics asserts that snbstances have specific mea-snrable macroscopic properties, but it cannot explain why a particular substance has particular numerical values for these properties. Thermodynamics can determine whether a process is possible, but it cannot say how rapidly the process will occur. For example, thermodynamics predicts that diamond is an unstable substance at atmospheric pressure and will eventually become graphite, but cannot predict how long this process will take. 

The principles that form the foundation of thermodynamics are embodied in several laws referred to as the laws of thermodynamics. In addition, thermodynamic functions, which interrelate the various properties of a system, are derived on the basis of these laws. A system refers to a part of space under consideration through whose boundaries energy in its different forms, as well as mass, may be transferred. 

The foundations of thermodynamics rest on two laws. The first law of thermodynamics defines a function of state, the energy, and restricts the region of conceivable processes to those in which the energy is conserved. The second law determines the direction in which the possible processes will proceed in a given system. These laws represent the formalization of a large number of experimental observations. No violations of these laws have been observed, and it is clear, from microscopic statistical mechanical considerations, that the occurrence of such violations is so improbable that they may be considered to be impossible. 

It is most amazing that scientists such as Carnot and Clausius, who laid the foundations of thermodynamics, still believed in a very naive caloric theory of heat, which held that heat is a form of fluid. The main practical question they faced was the following. Suppose there is some hot steam coming from a boiler. How much of its energy can it give away to produce useful work (Presumably, it cannot give up all its heat ) In other words. 

The foundations of thermodynamics are three facts of ordinary experience. These may be expressed very roughly as follows ... 

Hutter, K., The Foundations of Thermodynamics, Its Basic Postulates and Implications. A Review of Modem Thermodynamics , Acta Mechanical , 1-54 (1977). 

There are many published studies on the foundations of thermodynamics from a philosophical perspective, which make scant reference to applications to materials. They are often concerned with the second law and the nature of entropy and their epistemological implications. A large number of technical books give the mathematical details of the application of the theory to chemical problems without... 

We proceed with a discussion - again brief - of the Foundations of thermodynamics the Laws and the Thermophysical data, so that we become aware of their importance from the very beginning of this endeavor. 

Having finished with the Vocabulary of thermodynamics, we turn next to the second objective of this Chapter a brief discussion of the Foundations of thermodynamics, depicted pictorially in Figure 1.3 ... 

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