What is Sublimation? Definition, Meaning & Example
Sublimation is the process by which a solid changes directly to gas without passing through the liquid phase.
TL;DR: Sublimation is the process by which a solid changes directly to gas without passing through the liquid phase.
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Sublimation: Sublimation is the process by which a solid changes directly to gas without passing through the liquid phase.
Explanation
Sublimation occurs when molecules in a solid have enough energy to escape directly into the gas phase. Dry ice, which is solid carbon dioxide, sublimes at room temperature, disappearing into carbon dioxide gas without melting. Iodine crystals also sublime when heated. Naphthalene, used in moth balls, sublimes slowly at room temperature. Sublimation requires less energy than melting followed by evaporation. Ice can sublime when exposed to very low humidity and cold temperatures. Sublimation is the reverse of deposition, where gas changes directly to solid. Understanding sublimation is important in chemistry, physics, and freeze-drying processes.
Example
Dry ice sublimes at room temperature, transforming directly from solid to carbon dioxide gas without becoming liquid.
Frequently Asked Questions
Why does dry ice sublime instead of melt?
At normal atmospheric pressure and room temperature, carbon dioxide cannot exist as a liquid. The solid directly transforms to gas because the conditions favor the gas phase. This is why dry ice is useful for cooling without leaving liquid residue.
What is the opposite of sublimation?
The opposite of sublimation is deposition, where a gas transforms directly to a solid. Frost forming on windows is an example of deposition where water vapor becomes solid ice directly.
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