Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Cesium on October 09, 2007, 06:21:50 PM
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There is defiantly the change from solid to gas, the process of sublimation, but is it possible, to have the gas state of mater, turn straight to solid, skipping the liquid stage? If sublimation occurs by surface area gaining enough energy to make it vaporize, could the vapor of the object loose so much energy that it anti-sublimates?
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In some languages this process is called "resublimation".
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Ok thanks, how does it happen?
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We always called it deposition.
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Dear Cesium,
Have you ever heard about something called “PhaseDiagrams”?
A “PhaseDiagram” is able to tell you, which Aggregate state your compound/matter will have/”survive” for a certain Temperature/Pressure combination.
(X-Axis: Temperature, Y-Axis: Pressure)
On a border line in the diagram two Aggregate states exists at the same time, and at a “Triple point” (where two border lines met) three Aggregate states exists at the same time.
If you are able to find a border line between the solid and the gaseous state, so you know, that you can cross the border in both directions by in-/de-creasing the corresponded physical parameter.
One direction on the solid/gaseous border is called sublimation, and opposite is called deposition or sometimes anyway “condensation”.
If you combine both directions you can purify compounds very effective, and the whole process is anyway called “sublimation”, too.
“PhaseDiagrams” can become more complicated as soon as they combine more than one pure substance/matter lonely!
There is a Lot of literature about “PhaseDiagrams” A simple but very special PhaseDiagram you can find for water with its “Anomaly”.
Good Luck!
ARGOS++
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One direction on the solid/gaseous border is called sublimation, and opposite is called deposition or sometimes anyway “condensation”.
I'd imagine if they put "condensation" on a quiz/exam, that would be considered wrong. I know you said "sometimes anyway", but...yea. Condensation is typically only gas -> liquid
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Look at the phase diagram of CO2:
http://www.chem.uncc.edu/faculty/murphy/1252/Chapter11B/sld004.htm