Thermodynamics is the study of energy and how it is converted from one form to another. Thermodynamic principles are found in physics, chemistry, biology, engineering, and material science courses, as well as many other scientific disciplines. In any situation where heat or energy are considered, thermodynamics plays a vital role. With the exception of the sun, most of the energy we use in our everyday lives comes from chemical reactions. By studying the energy changes that accompany chemical reactions, chemists can use thermodynamic principles to improve a variety of applications, from heating your apartment, to designing materials to line your jacket and keep you warm on a cold winter day, to finding the proper mixture of fuel to power your automobile.
In order to have an educated discussion about energy we must first have an understanding of the units chemists use and we need to be able to define a system and its surroundings.
5.1 The Nature of Energy