What is the process where a gas transforms directly into a solid called?

The process where a gas transforms directly into a solid is called deposition. This phenomenon occurs without passing through the liquid phase, meaning that the gas particles lose energy and transition straight to a solid state.

One common example of deposition is frost forming on surfaces when water vapor in the air cools and transitions directly into ice. It is an essential concept in physical chemistry, as it highlights how matter can change states under varying conditions of temperature and pressure.

In contrast, sublimation refers to the process where a solid transitions directly into a gas. Condensation involves the transformation of gas into a liquid, while evaporation pertains to the process of a liquid turning into a gas. Understanding these distinct processes is crucial for grasping the broader concepts of phase changes in chemistry.