Which of the following best describes sublimation?

• A. A physical change in which a solid turns directly into a gas without passing through the liquid phase.
• B. A chemical change in which a solid reacts to form a gas.
• C. A physical change in which a liquid turns into a solid.
• D. A chemical change in which a gas condenses to form a solid.

Answer: (A)

Verified step by step guidance

1. Understand the definition of sublimation: it is a phase transition where a substance changes directly from the solid phase to the gas phase without passing through the liquid phase.
2. Recognize that sublimation is a physical change because the substance changes its state of matter but its chemical identity remains the same.
3. Eliminate options that describe chemical changes, as sublimation does not involve a chemical reaction or formation of new substances.
4. Eliminate options that describe phase changes involving liquids, such as freezing (liquid to solid) or condensation (gas to liquid or solid), since sublimation skips the liquid phase entirely.
5. Conclude that the best description of sublimation is: 'A physical change in which a solid turns directly into a gas without passing through the liquid phase.'