SiedetemperaturFlüchtigkeit

Siedetemperatur refers to the boiling point of a substance. It is the temperature at which a liquid turns into a gas or vapor at a given pressure. This transition occurs when the vapor pressure of the liquid equals the surrounding atmospheric pressure. At the boiling point, the liquid absorbs heat energy, which is used to overcome the intermolecular forces holding the liquid molecules together, allowing them to escape into the gaseous phase.

The boiling point is an intrinsic property of a substance, meaning it is a characteristic that does not depend on the amount of the substance. However, it is significantly influenced by external pressure. At higher atmospheric pressures, a higher temperature is required for the liquid's vapor pressure to reach the surrounding pressure, thus increasing the boiling point. Conversely, at lower pressures, the boiling point decreases. This is why water boils at a lower temperature at high altitudes where atmospheric pressure is reduced.

Pure substances have a specific and constant boiling point at a standard atmospheric pressure (1 atmosphere or 101.325 kilopascals). For example, pure water boils at 100 degrees Celsius (212 degrees Fahrenheit) at standard atmospheric pressure. The presence of dissolved impurities, such as salt in water, can elevate the boiling point. This phenomenon is known as boiling point elevation and is a colligative property, meaning it depends on the concentration of solute particles rather than their identity.