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Concept of Entropy

  1. Dec 2, 2014 #1
    What is entropy ?, And how it effect the system?
  2. jcsd
  3. Dec 2, 2014 #2


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    Gold Member

    Have you done ANY research on your own? What do you know about it so far?
  4. Dec 2, 2014 #3
    Not actualy researched but ,

    the only thing i know about it,
    is, the entropy is a matter of order or disorder of molecules

    but , problem is that , i just wanted to know cocept behind it

    what does it mean actually???, So
  5. Dec 2, 2014 #4
    Entropy is defined as the amount of disorder in a system.
    Thats just a conceptual definition.
    For example, take a box full of, say a 100 molecules in a gas phase.
    If the temperature is near absolute zero, each molecule can only move in a limited zone.
    But, if I up the temperature, to say 373 K, all the molecules start whizzing about in a much more increased span of space. Not just that, but they also collide with each other more frequently and have more disorder, or entropy, as we say.
    As you see, the concept of entropy is related to the temoerature of a system.
    If the temperature of a body is altered, so is its molecular movement and thus its entropy.
    Mathematically, on heating or cooling a body, we take a small frame of time in which the temperature stays constant, and then figure out the really small change in heat dQ. The CHANGE In entropy is then defined as
    dQ/T (T is temperature in KELVIN scale.)
    For a large change in temperature, we take all the small changes in entropy and add them up. If you're a calculus student, you'll know this is just integrating the expression dQ/T.
  6. Dec 2, 2014 #5

    Doug Huffman

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    To make the conceptual leap to the entropy of information, it is a measure of the number of bits to fully describe those 100 molecules.
  7. Dec 2, 2014 #6
    Ok ....
    so if system having 100 Molecules as u said is consider
    and temp. Of system is increses means disorderness is incresed

    can we say that with increse in entopy chances of loss of heat is more ( If system is open and other than isothermal )

    so , can we relate entropy with loss of heat ????
  8. Dec 2, 2014 #7
    What do u mean sir !?!

    can u elaborate in simple words?
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