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Homework Help: Spontaneity of physical processes

  1. Sep 6, 2012 #1

    there is no law that says that processes occur physically towards the energy minimization of the system

    however, there is a law (second thermodynamic) that says that processes occur physically towards the entropy maximization

    1) so, why do we need ΔG (Gibbs free energy) to predetermine a process' direction?

    2) also, why ΔG is depended to temperature?

    3) I have seen in a tutorial where they said that moving from primary to secondary and to tertiary etc, protein structure, it is a increases in protein's entropy! in a textbook, I read the opposite (which is more correct imo, since a folded protein has some fixed substructures, thus the number of possible structures is limited)
    which is the correct? and if folding decreases its entropy, how is this thermodynamically compliant?

    4) what is the difference of enthalpy and free energy of a biochemical system?

    Last edited: Sep 6, 2012
  2. jcsd
  3. Sep 6, 2012 #2


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    Gold Member

    1) Gibbs Free Energy is a thermodynamic potential which determines the non-PV work or "useful" work in initiating and proceeding a process.

    2.) Check the formula for Gibbs Free Energy. Usually, at higher temperatures, processes proceed more easily, even the non-spontaneous, difficult to get products can be formed.
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