When a substance changes directly from the solid state to the gaseous state without forming a liquid, the substance is said to

When a substance changes directly from the solid state to the gaseous state without forming a liquid, the process is called sublimation. This means that the solid substance goes through a phase change and turns into gas without passing through the liquid phase. The term "sublime" is used to describe this process. For example, dry ice, which is solid carbon dioxide, undergoes sublimation when it is exposed to room temperature or higher temperatures, and turns directly into carbon dioxide gas without forming a liquid. Similarly, iodine crystals, which are solids, can sublime when heated, forming purple vapors of iodine gas.