ABSTRACT
This chapter examines the physical behavior of gases, first by assuming gases behave ideally, then considering the behavior of real gases and how they differ from ideal gases. It focuses on a physical behavior of gases and gas mixtures. A pure gas is one made up of individual atoms, molecules made from one type of atom or compound molecules made from a variety of atoms. At the microscopic level, what distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. Only absolute pressure has any significance in thermodynamics, and relative pressure values must be converted to absolute pressure for thermodynamic calculations. The ideal gas law can be derived from principles from the kinetic theory of gases in which simplifying assumptions are made. Various equations have been proposed to express the equation of state for gases that deviate significantly from ideality.
