What do you call a solid changing to a gas?

What do you call a solid changing to a gas?

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

Answer: (A)

Directly changing from a solid to a gas is sublimation. This happens when a solid has enough vapor pressure at a given temperature that its molecules escape into the gas phase without melting first. It’s typically driven by heat input, since energy is needed to overcome the forces holding the solid together. A common example is dry ice, which at room temperature and pressure sublimates into carbon dioxide gas. By contrast, condensation is gas turning into liquid, deposition is gas turning into a solid, and fusion (melting) is solid turning into liquid.

Directly changing from a solid to a gas is sublimation. This happens when a solid has enough vapor pressure at a given temperature that its molecules escape into the gas phase without melting first. It’s typically driven by heat input, since energy is needed to overcome the forces holding the solid together. A common example is dry ice, which at room temperature and pressure sublimates into carbon dioxide gas. By contrast, condensation is gas turning into liquid, deposition is gas turning into a solid, and fusion (melting) is solid turning into liquid.