Mättnadstryck

Mättnadstryck, also known as saturation pressure, refers to the pressure at which a substance exists in equilibrium between its liquid and gaseous phases at a given temperature. At this specific pressure, the rate at which molecules evaporate from the liquid surface is equal to the rate at which gas molecules condense back into the liquid. This state of dynamic equilibrium means that the amount of liquid and gas remains constant.

If the pressure above the liquid is below the saturation pressure, the liquid will tend to evaporate until it is all gone or until the pressure reaches saturation pressure. Conversely, if the pressure is above the saturation pressure, the gas will tend to condense into a liquid. The saturation pressure is a property of the substance and increases with increasing temperature. For example, water at 100 degrees Celsius has a saturation pressure of 1 atmosphere. At any other pressure at this temperature, water will be either entirely liquid or entirely steam. This concept is crucial in thermodynamics and various engineering applications, such as refrigeration cycles and steam power plants, where understanding phase transitions is essential for efficient operation.