Thermodynamics is a branch of physics which is associated with the energy and work of a system. Thermodynamics treaties only with the large scale response of a system which we can observe and measure in experiments. Small scale gas interactions are described by the kinetic theory of gases. The methods complement each other; some principles are more easily understood in terms of thermodynamics and some principles are more easily explained by kinetic theory. Historically, thermodynamics arose from the study of two distinct kinds of transfer of energy, as heat and as work, and the relation of those to the system's macroscopic variables of volume, pressure and temperature. As it developed, thermodynamics began also to study transfers of matter. Initially, thermodynamics, as applied to heat engines, was concerned with the thermal properties of their 'working materials', such as steam, in an effort to increase the efficiency and power output of engines. Thermodynamics was later expanded to the study of energy transfers in chemical processes, such as the investigation of the heats of chemical reactions by Germain Hess, which was not originally explicitly concerned with the relation between energy exchanges by heat and work. From this evolved the study of chemical thermodynamics and the role of entropy in chemical. Thermodynamics applies to a wide variety of topics in science and engineering, especially physical chemistry, chemical engineering and mechanical engineering. Fundamentals of Thermodynamics emphasizes on the study of heat, "thermo," and work, "dynamics." This book focuses on energy transfer during chemical and physical changes, and how we can predict what kind of changes will occur.