A liquid-gas system consists of two distinct phases: a liquid phase and a gas phase. These systems are commonly found in nature and industrial processes, such as in the atmosphere, where water vapor exists alongside liquid water. The interaction between the liquid and gas phases can lead to various phenomena, including evaporation and condensation. In a liquid-gas system, the properties of each phase can influence the overall behavior of the system. For example, temperature and pressure changes can affect the equilibrium between the liquid and gas phases. Understanding these systems is essential in fields like thermodynamics and chemical engineering.