Systems, States, and Processes

This chapter lays the groundwork: Thermodynamic systems are introduced as finite domains with well-defined boundaries, which might be closed or open. Complex systems can be considered as compounds of many smaller and simpler systems. The system state is defined through the type and amount of matter in the system, and the values of measurable properties, such as temperature, pressure, volume. Important properties and their units are introduced. Starting with simple processes from daily experience, thermodynamic processes are introduced as changes of the state of the system, with the tendency to approach unique and stable equilibrium states. Processes might occur spontaneously to reach equilibrium states, or might be induced by manipulation, where irreversible and quasi-equilibrium processes must be distinguished. Some emphasis lies on the introduction of temperature and pressure as measurable properties.