When does boiling occur?

Boiling occurs when the total vapor pressure of a liquid equals the atmospheric pressure surrounding it. This condition allows bubbles of vapor to form within the liquid, rise, and escape into the air, which is the visual sign of boiling. When the vapor pressure matches atmospheric pressure, the molecules within the liquid have enough energy to break free from intermolecular forces and enter the gas phase.

In the context of boiling and vapor pressure, it is important to understand that if the total vapor pressure is greater than atmospheric pressure, boiling will also occur, but that is not the defining moment of boiling itself. Instead, it is the moment when the vapor pressure reaches the same level as the surrounding pressure that initiates the phenomenon.

This understanding is crucial in practical applications, such as cooking or distillation, as it determines the boiling point of various substances under different atmospheric conditions. Thus, boiling can be succinctly described as the process triggered by achieving a state where vapor pressure and atmospheric pressure coincide.