What is the process called when a substance changes from a liquid to a gas?

Vaporization refers to the process where a substance transitions from a liquid state to a gaseous state. This occurs when the molecules within the liquid gain enough energy to break free from the bonds holding them together, leading to the formation of vapor. This process can happen in any part of the liquid and is primarily associated with the concept of boiling, where the temperature of the liquid reaches a point that allows for rapid vaporization throughout the volume of the liquid.

Evaporation is a specific type of vaporization that occurs at the surface of a liquid at temperatures below its boiling point and can happen over a longer period, while boiling (a more general term for vaporization) happens throughout the liquid. Condensation, on the other hand, is the opposite process where gas turns into a liquid, and melting refers to the transition from solid to liquid. Thus, vaporization encompasses both evaporation and boiling, making it the correct choice for when discussing the general process of a liquid transforming into a gas.