Sublimation

The process of sublimation cartoon

The process of sublimation cartoon

Sublimation is the process of turning from solid to vapor without going through the intermediate liquid phase.

WHAT TYPE OF SOLID SUBLIMES?

We all know that ice melts before it evaporates. In sublimation, the liquid phased is omitted. In order for a solid to sublime, it must exhibit a higher than usual vapor pressure and weak intermolecular attractions.

Read more about vapor pressure.

Sublimation in the refrigerator

Sublimation process in the refrigerator

  • Have you ever noticed ice cubes left in the freezer shrink over time?
  • The freezer has the right condition for ice cubes to sublime – that for them to turn into water vapor without first melting.
  • Low temperature
  • Low humidity
  • Can you explain why that is the case?

 

Low temperatures lead to low humidity which in turn creates a low pressure environment. So molecules in the ice cubes in the freezer are able to overcome the intermolecular forces which hold them together tightly and they are able to move far apart from each other. This is how ice can sublime.

A solid Carbon Dioxide compound can sublime at 1 atm atmospheric at 78.5°C (http://webapps.utsc.utoronto.ca/chemistryonline/sublimation.php).

Leave a Reply

Your email address will not be published.