Which of the following best describes sublimation, and which is an example of this process?

• A. Sublimation is the process of a gas turning into a liquid; an example is water vapor condensing to form dew.
• B. Sublimation is the melting of a solid into a liquid; an example is ice melting to form water.
• C. Sublimation is the direct transition from solid to gas without passing through the liquid phase; an example is dry ice (solid CO_2) turning into carbon dioxide gas.
• D. Sublimation is the conversion of a liquid to a solid; an example is water freezing to ice.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the definition of sublimation. Sublimation is a phase transition where a substance changes directly from a solid to a gas without passing through the liquid phase.
2. Step 2: Review the other phase changes mentioned: condensation (gas to liquid), melting (solid to liquid), and freezing (liquid to solid). These are different from sublimation.
3. Step 3: Identify the example that matches the definition of sublimation. Dry ice (solid CO_2) turning directly into carbon dioxide gas is a classic example of sublimation.
4. Step 4: Confirm that the other examples do not fit sublimation because they involve intermediate liquid phases or different phase changes.
5. Step 5: Conclude that the correct description and example of sublimation is the direct transition from solid to gas, exemplified by dry ice sublimating.