What does sublimation refer to?

Sublimation specifically refers to the phase transition where a substance moves directly from the solid state to the gas state, bypassing the liquid phase entirely. This process occurs under certain conditions of temperature and pressure, usually when the temperature is low and the pressure is also low, allowing solid molecules to gain enough energy to escape into the gas phase without first becoming liquid.

For example, dry ice (solid carbon dioxide) sublimates at room temperature, transforming directly into carbon dioxide gas. This is an important concept in physical chemistry and has various applications, such as in freeze-drying processes. Understanding sublimation helps in recognizing how different substances transition through their phases under varying conditions.