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Creation and Destruction of Entropy

  1. Oct 17, 2004 #1
    ¿ Can entropy be simultaneously created and destroyed in different partes of the universe of a process?
     
  2. jcsd
  3. Oct 18, 2004 #2
    I thought entropy was a measure of disorder? We've done about it in Chemistry, and I was under the impression that it always increased? If this is the case, surely it can't be destroyed? Just thinking out loud here though, I really don't know!
     
  4. Oct 18, 2004 #3
    You don't "create" and "destroy" entropy. You can locally decrease entropy, but by doing so, you must make some energy conversions,thereby still increasing the total entropy of the universe.
     
  5. Oct 22, 2004 #4
    geometer:
    I agree with your comments in relation to the total entropy change of the universe. But my question refers to a term called production of entropy ( creation of entropy) , proposed by Prigogine (Nobel Prize In Chemistry). He proposes that :
    dS= dQ/T + dSi
    where dSi is the production or creation of internal entropy ( Thermodynamics of Irreversible Processes, Thir Ed. InterScience Publishers, 1967).
    According to Prigogine, dSi is always equal or greater than zero. But, I have found a process in which this term, is simultaneosly positive( creation of internal entropy) and negative ( destruction of internal entropy) in different parts of the universe, and the total entropy change of the universe is greater than zero. The fact, that the total entropy change is greater than zero suggest that the process is allowed by thermodynamics laws.
     
  6. Oct 23, 2004 #5
    Hi
    Can u please tell us the process in which internal entropy production is negative?
    It might be possible that in self organizing systems that organize themselves like living matter...or other complex systems...but it also occurs at expense of energy...thus increasing overall entropy...again with the law...
    the only shortcoming of 2nd law is the EXACT value of increase of entropy....
    so the present STATUS of this law is that it is phenemological and QUALITATIVE....once this extension is done it will recieve the status of a law.
     
  7. Oct 24, 2004 #6

    Totally agree.

    Well by definition dSi is positive or equal to zero ( equal to zero for a reversible transform and positive for irreversible one.) And we don't see it is not used only in chemistry
     
  8. Oct 29, 2004 #7

    Several years ago I published an article related to the theoretical existence of a process that creates and destroys entropy in differente regions of the universe. The article was published in the Journal of Chemical Education ( Vol 72, page 116, February 1995) and generated many positive and negative critics. However, nobody could find errors or fundamental transgressions.
    The theoretical process consists of two tanks A and B separated by a metallic partition of a good heat conducting metal. The adiabatic film can be removed or put back in place during process operation if desired. Tank A is fitted with a piston and tank B is a rigid box. The boundaries of the tanks in contact with the surroundings are adiabatic. In both tanks there is 1 g-mol of a monoatomic ideal gas. Initially the metal partition is covered with the adiabatic film . Then, then the ideal gas in A is set at 1500 K and 101.33 kpa, and the ideal gas in B is set at 373 K and 101.33 kpa.When these conditions are reached in both tanks the adiabatic film is removed and and the following process starts. In tank A the gas is compressed isothermally in a non reversible way at 1500 K from 101.33 kpa to 405.32 kpa., and work is done on the ideal gas ,and heat is transferred through the metal partition to the ideal gas in tank B. The gas temperature in B increases, and the compression in A is stopped when the temperature in B reaches 1500 K. Then the process is finished.
    The calculations ( presented in the above article) show that at these conditions the total entropy change of the iniverse is greater than zero and that entropy is produced ( created) due to the heat flow through the metal partition and destroyed in the compression process taking place in tank A. Since, the total entropy change of the universe is greater than zero , the process is permitted by the second law of thermodynamics.
    After this publication, I have found other thermomechanical systems that present a similar behavior.
     
  9. Oct 30, 2004 #8

    russ_watters

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    Staff: Mentor

    Maybe I'm missing the point, but pretty much every thermodynamic process works the same way, Iraides. That's one of the main points of thermodynamics.
     
  10. Nov 1, 2004 #9
    russ watters:
    Most of the thermodynamics processes produces ( creates) entropy but they do not destroy ( absorpt) entropy. Above process is a theoretical exception to this behavior.
     
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