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Understanding Entropy better

  1. Aug 19, 2011 #1

    I've been recently learning thermodynamics and have some questions about entropy. First off, I understand that it is a statistical measure of disorder and uncertainty and understand the 2nd and 3rd laws fairly well.

    My question pertains more to Gibb's Free Energy. As I've learned it, there is only a certain amount of usable energy that can be done as non-expansion work that is equal to enthalpy - temperature*entropy. Thus, I am querying if there is something more to entropy than statistic. Does a system that has increased in entropy increased in energy, and some type of energy that is bound to entropy only? Is the disorder increase related to this unusable energy? I guess I'm wondering if entropy is somehow physical rather than just mathematical.
  2. jcsd
  3. Aug 19, 2011 #2


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    The answer is that entropy is more complicated than that. You're not going to get it from studying thermodynamics. You need to study statistical mechanics to get a better hang of entropy, and you really need some basic understanding of quantum mechanics to understand it properly.

    If you are just studying thermodynamics, don't worry too much about what entropy actually is.
  4. Aug 19, 2011 #3


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  5. Aug 19, 2011 #4
    Well, its more for my own interest of understanding entropy. I was trying to figure out if the the energy that can't be used as work was somehow related to the number of microstates or something like that and if so, how.
  6. Aug 20, 2011 #5
  7. Aug 20, 2011 #6
    I think that entropy doesn't contribute to increase in "unusable energy". It's just transformation of energy usually increases overall entropy because energy transformation transmits information.

    Free energy associates with temperature, and it's apparent that hotter the system is, more disorder the arrangement is.
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