Thermodynamics

Thermodynamics is the study of how heat and temperature relate to energy and work (Wikipedia). Thermodynamics became a formal field of study in 1824 when Sadi Carnot published Reflections on the Motive Power of Fire, which discussed heat, power, energy, and efficiency. Carnot also designed the Carnot Heat Engine, which runs on a reversible cycle that has is the most efficient way to convert energy into work.

William Rankine wrote the first thermodynamic textbook in 1859 (see the research papers page for a link to this text). Rankine is also known for proposing his own temperature scale, and theorizing a Rankine cycle, which is a heat engine with a condenser.

The laws of thermodynamics which guide this field of study are:

0th: Two systems that are in thermal equilibrium with a third system, must also be in thermal equilibrium with each other.

1st: Energy can not be created or destroyed, therefore the total energy of an isolated system is constant.

2nd: The entropy of a system spontaneously proceeds to the state of maximum entropy.

3rd: The entropy of a substance at absolute zero is equal to zero.

The seven topics chosen for this website are important because they are all key concepts related to the laws of thermodynamics.

In chemical engineering, thermodynamics is used to model heat engines and refrigerators, determine the heat and energy produced in reactions, and the amount of work needed to power systems.

All of the concepts of thermodynamics depend on the definition of the system and its surroundings. Once a system is defined, the laws of thermodynamics can be applied to help determine the internal energy and enthalpy, as well as entropy.

When a reaction is being studied, it is important to know if it is at equilibrium or steady state to know what is flowing into and out of the system. If different amounts of products are desired from the reaction, being able to manipulate the reaction rate and equilibrium state is also important. In the case of a binary system at its boiling point, a vapor-liquid equilibrium curve will allow the determination of the compositions in both the vapor and liquid phases.

If the reaction or system is part of a cycle, the highest possible efficiency is desired. To achieve this, the process should be as close to reversible as possible.