What does the term 'Vapor Pressure' refer to?

Vapor pressure specifically refers to the pressure exerted by a vapor when it is in equilibrium with its liquid or solid phase. This concept is critical in understanding how a substance transitions between its different states of matter, particularly in processes like boiling and evaporation. When a liquid is heated, molecules gain energy and some escape into the vapor phase, creating vapor pressure. At equilibrium, the rate of molecules escaping into the vapor equals the rate of molecules returning to the liquid, and the pressure exerted by this vapor is the vapor pressure.

This property is important for various applications, such as determining boiling points, understanding weather phenomena, and in various chemical processes where phase changes occur. The significance of vapor pressure highlights its role in thermodynamics and fluid mechanics, making it an essential concept for anyone studying power engineering or related fields.