Step 1: Understanding the Concept:
Phase transitions describe the physical transformation of matter from one state (solid, liquid, or gas) to another in response to changing temperature or pressure.
Step 2: Key Formula or Approach:
The approach requires identifying the specific thermodynamic term assigned to the endothermic phase change from a solid directly to a gaseous state.
Step 3: Detailed Explanation:
Sublimation is the specific phase transition in which a substance moves directly from the solid phase to the gas phase.
Crucially, this occurs without the substance ever passing through the intermediate liquid phase.
A classic real-world example is dry ice (solid carbon dioxide), which turns directly into cold carbon dioxide gas when exposed to room temperature and pressure.
Condensation is the transition from a gaseous state back into a liquid state.
Evaporation is a type of vaporization that occurs on the surface of a liquid as it transitions into the gas phase.
Deposition is the direct reverse of sublimation, where a gas transforms directly into a solid without becoming a liquid first, such as frost formation.
Step 4: Final Answer:
The process of a solid turning directly into a gas is called sublimation.