Name: Sharon
Status: educator
Grade: 9-12
Location: CO
Date: May 2008
Question:
I am tutoring a young lady in Science, and in her textbook
there is a table that gives the melting and boiling points of
various substances. For the gas dihydrogen sulfide, it gives a
melting point of -85 degrees/C. She asked how can a gas "melt", and
what state is it in after it melts? I have no idea. Can you help?
Replies:
but that is not always the case. On a cold, dry, day water (in the form of ice
crystals) sublimes directly from the solid phase to the vapor phase. "Dry ice"
sublimes from the solid into the vapor without entering the intermediate liquid
phase. Usually, it is the evaporation of a liquid phase at a pressure of 1 atm
is stated as "the boiling point"; however, a substance can evaporate from either
the liquid or solid phase at some other applied pressure less than 1
atmosphere.
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