Saturday, 31 January 2015

DRY ICE TRANSFORMS DIRECTLY TO FROM BEING A SOLID TO A GAS (WITHOUT TURNING TO LIQUID)


Dry ice, sometimes referred to as "cardice" (chiefly British chemists), is the solid form of carbon dioxide. It is used primarily as a cooling agent. Its advantages include lower temperature than that of water ice and not leaving any residue (other than incidental frost from moisture in the atmosphere). It is useful for preserving frozen foods, ice cream, etc., where mechanical cooling is unavailable.
Dry ice sublimes at −78.5 °C (−109.3 °F) at Earth atmospheric pressures. This extreme cold makes the solid dangerous to handle without protection due to burns caused by freezing (frostbite). While generally not very toxic, the outgassing from it can cause hypercapnia due to buildup in confined locations.
Camphor is also another substance that possesses this sublimation property.

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