To understand thermodynamics, you need to know the definitions of the following terms:

• System: A system is defined as a quantity of matter, region, or space where focus is on the effect of transfer or transformation of energy from one form to the other. It can be open, closed, or Isolated system depending upon the transfer of heat energy and mass transfer.

• Property: Any measurable characteristic of a system is defined as a property of the system, such as pressure (P), temperature (T), volume (v), and mass (m). The properties per unit mass are known as specific properties, such as specific volume, specific enthalpy, specific internal energy, and specific entropy.

• State: When a system with fixed properties reaches a stable condition, the system is said to reach a state. Any change of state is allied with the change in properties of the system. As a result, the properties of a system depend on its state but the state of a system does not depend on its properties.

• Process: When a change in state takes place during the transformation or transfer of energy, a process is said to have been performed. The two common processes of thermodynamics are isenthalpic (at constant enthalpy) and isentropic (at constant entropy).