Careers: Chemistry/physical chemistry

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Expert: - 6/28/2010


Question
What will happen if a mixture of ice and water is pressurized. More ice will form or ice melt to water or nothing happen?

Answer
First, pull up this phase diagram of water:
http://www.its.caltech.edu/~atomic/snowcrystals/ice/h2ophase.gif

Basically you are talking about something that is sitting at the cusp of the water and ice phase.  We will assume that the mixture begins at the point in the lower left (atm 1, 0 deg. C).  Now, go up the diagram (increase pressure) and you will see that this puts us clearly in the water region.  This means that the ice will melt to some degree.  This is a unique property of water, and cannot be taken as the rule for most materials.  This effect is due to the crystal structure of normal ice.  Normal ice is less compact than liquid water do to extra space generated from the hydrogen bonds.  As you apply pressure, the less dense material (ice) will have a tendency to transition to the more dense phase (water).  As a side note, with no change in temperature, it may be difficult to melt all the ice this way.  However, from thermodynamics we know that a rise in P equates to a rise in T, so we would probably expect the temperature to rise as well making the ice to water transition even more likely.

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Volunteer

Dr. Jeffery Raymond

Expertise

Materials chemistry. Materials science. Spectroscopy. Polymer science. Physical Chemistry. General Physics. Technical writing. General Applied Mathematics. Nanomaterials. Optoelectronic Behavior. Science Policy.

Experience

Teaching: General Inorganic Chemistry I & II, Organic Chemistry I & II, Physical Chemistry I, Polymeric Materials, General Physics I, Calculus I & II
My prior experience includes the United States Army and three years as a development chemist in industry. Currently I am the Assistant Director of the Laboratory for Synthetic Biological Interactions. All told, 13 years of experience in research, development and science education.

Organizations
Texas A&M University, American Chemical Society, POLY-ACS, SPIE

Publications
Journal of the American Chemical Society, Nanoletters, Journal of Physical Chemistry C, Journal of Physical Chemistry Letters, Ultramicroscopy Proceedings of SPIE, Proceedings of MRS, Polymer News, Chemical and Engineering News, Nano Letters, Small, Chemistry.org, Angewandte

Education/Credentials
PhD Macromolecular Science and Engineering (Photophysics/Nanomaterials Concentration), MS Materials Science, BS Chemistry and Physics, Graduate Certificate in Science Policy, AAS Chemical Technology, AAS Engineering Technology

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