Sublimation
Definition and meaning of Sublimation in chemistry.
Sublimation is the fascinating physical phase transition of a substance directly from the rigid solid state to the diffuse gas phase without ever passing through the intermediate liquid phase. It is an explicitly endothermic thermodynamic process that occurs strictly at temperatures and pressures located below a substance's unique triple point in its phase diagram.
In more detail
During the process of sublimation, individual molecules in the solid matrix absorb enough ambient heat energy to completely overcome the strong intermolecular attractive forces holding them together, escaping directly into the free vapor state. The process requires a specific environmental combination of relatively low atmospheric pressure and appropriate temperature to proceed efficiently. Sublimation is widely utilized in specialized laboratory purification techniques for volatile organic compounds, in the commercial freeze-drying of food to preserve nutrients, and in specialized modern dye-sublimation printing processes.
Key facts
| Field | Physical Chemistry |
|---|---|
| Formula | CO2 |
| Phase change | Direct transition from solid to gas |
| Thermodynamics | Highly endothermic process requiring heat |
Dry ice, which is solid carbon dioxide (CO2), rapidly sublimates directly into cold carbon dioxide gas at standard room temperature and normal atmospheric pressure.
Frequently asked questions
What is the exact reverse thermodynamic process of sublimation called?
The direct transition from a gas directly down into a solid structure without becoming a liquid is properly called deposition.