Water Damage Restoration Technician (WRT) Certification Practice Test

Which process occurs when a solid changes directly to a vapor without becoming a liquid?

1. Condensation

2. Evaporation

3. Sublimation

4. Freezing

The correct answer is: Sublimation

The process where a solid changes directly into a vapor without passing through the liquid state is known as sublimation. This phenomenon occurs under specific conditions of temperature and pressure, allowing solid molecules to gain energy and enter the gas phase directly. Sublimation is commonly observed in substances like dry ice (frozen carbon dioxide), which transitions from solid to vapor without becoming liquid. Condensation refers to the process where a gas transitions into a liquid, which is the opposite of sublimation. Evaporation, on the other hand, is the conversion of a liquid into vapor, not applicable here as it involves an intermediate liquid phase. Freezing describes the change from a liquid to a solid, which also does not relate to the solid-to-vapor transition. Thus, sublimation is the correct term that captures the essence of a solid directly converting into vapor.