What is the process called when a solid turns directly into gas?

The process where a solid turns directly into gas is called sublimation. This transition occurs without passing through the liquid state. Sublimation happens under certain conditions of pressure and temperature, which allow for a solid, such as dry ice (solid carbon dioxide), to change directly into its gaseous form without becoming a liquid first. This process is used in various applications, including freeze-drying and cleaning methods, where maintaining the solid's integrity while removing moisture is essential.

In contrast to the other processes, condensation refers to the transformation of gas to liquid, vaporization encompasses the conversion of liquids to gas, and evaporation is a specific form of vaporization that occurs at the surface of a liquid. Understanding these different processes is crucial as they relate to phase changes and the states of matter in chemistry.