Talk:Second law of thermodynamics

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Revision as of 21:00, 6 November 2009 by imported>Milton Beychok (→‎Revised Metadata template: new section)
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 Definition Entropy S is a state variable of a thermodynamic system; when a system of temperature T absorbs heat DQ reversibly, then dS = DQ/T; during an irreversible (spontaneous) state change dS > DQ/T. [d] [e]
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 Workgroup categories Physics, Chemistry and Engineering [Please add or review categories]
 Subgroup category:  Chemical Engineering
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What does "rest heat" mean?

Paul, in the "Discussion of the second law" section, you refer to Qc as the "rest heat". Did you mean "heat at rest" or did you mean "the rest of the heat" or the "remaining heat"? I made no changes, but I do think that if you meant "remaining heat", then the wording needs to be changed. Perhaps to "remainder heat"?

If, on the other hand, you really meant "heat at rest", then the wording also needs to be changed, because "rest heat" needs to be clarified as to what is meant. Milton Beychok 19:58, 6 November 2009 (UTC)

About the use of DQ

Paul, in the term DQ/T. What is D? is that meant to be Delta? If so, then I think it might be better to use the symbol δ or Δ. I am certainly not the mathematician you are by any stretch of imagination, but I simply have never seen that terminology used to denote a small amount of heat (or anything else). Milton Beychok 20:17, 6 November 2009 (UTC)

How about using this quote somewhere in this article?

The statement by Clausius that "Die entropy der welt strebt einem maximum zu" (The entropy of the universe tends (strives?) to a maximum) is one that that has stuck in my mind ever since I first heard it in a university thermodynamic class over 65 years ago. How about using that quote somewhere in this article? Milton Beychok 20:38, 6 November 2009 (UTC)

Revised Metadata template

Changed the cat "Chemical engineering" to sub "Chemical Engineering", because Chemical Engineering (with a captal E) is a subgroup. Also added the cat "Engineering". Milton Beychok 03:00, 7 November 2009 (UTC)