Sublimation
| Formula / Notation | Solid → Gas (no liquid phase); ΔH_sub = ΔH_fus + ΔH_vap |
|---|---|
| Also Known As | Sublimation process, solid-gas transition, vaporisation from solid |
What is Sublimation?
The phase transition in which a solid changes directly to a gas without passing through the liquid state. It requires energy equal to the sum of enthalpy of fusion and enthalpy of vaporization. Examples: dry ice (CO₂), iodine, and naphthalene sublimate at atmospheric pressure.
Formula & Notation
Other Names / Synonyms: Sublimation process, solid-gas transition, vaporisation from solid
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The phase transition in which a solid changes directly to a gas without passing through the liquid state. It requires energy equal to the sum of enthalpy of fusion and enthalpy of vaporization. Examples: dry ice (CO₂), iodine, and naphthalene sublimate at atmospheric pressure.
Sublimation is used to purify substances such as iodine, caffeine, and benzoic acid. Freeze-drying (lyophilisation) of food and pharmaceuticals exploits sublimation to remove water under low pressure. Dry ice (solid CO₂) sublimes at atmospheric pressure at -78.5°C.
Substances that sublime can accumulate in the atmosphere as toxic or asphyxiating vapours. Handling dry ice requires insulated gloves as it causes cryogenic burns. Iodine vapour is toxic and irritating.
The formula or notation for Sublimation is: Solid → Gas (no liquid phase); ΔH_sub = ΔH_fus + ΔH_vap