What is the term for the change of a substance from solid to gas without passing through the liquid state?

• A. Evaporation
• B. Condensation
• C. Sublimation
• D. Deposition

Answer: (C)

The change of a substance from solid to gas without first becoming liquid is referred to as sublimation. This process occurs when the molecules in a solid gain enough energy to break free from their rigid structure and transition directly into the gaseous state. An everyday example of sublimation is dry ice (solid carbon dioxide) which, when exposed to air, transforms into carbon dioxide gas without melting into a liquid.

In contrast, evaporation refers to the transition from liquid to gas, while condensation is the reverse process—gas to liquid. Deposition involves the transition from gas to solid without passing through the liquid phase. Understanding sublimation is important in various contexts, such as in climate science and the behavior of certain materials under specific conditions.