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Spontaneous Reactions

  1. Feb 16, 2010 #1
    If a reaction is spontaneous when calculated using Gibb's Free Energy formula,
    Delta G = Delta H - (T*Delta S)

    Does it mean the reaction will occur at impossible temperatures even (such as 999999999999999999999999 degrees Kelvin)

    for ex:
    H2O(g) C(s) --> CO(g)+H2(g)
    Delta H = 135.5 kJ
    Delta S = .1488 kJ
    T = 1173 Kelvin

    Delta G = -39 (if delta G is negative, the reaction is spontanious, according to Gibb's Free Energy)

    since this reaction is spontanious, will this occur at 99999999999999999 degrees kelvin even? (is this possible?)
  2. jcsd
  3. Mar 1, 2010 #2
    Theoretically, it is. But since you cannot achieve such a temperature, it has no practical significance.
  4. Mar 1, 2010 #3


    User Avatar

    Staff: Mentor

    No, it doesn't mean that. When temperature rises other effects/reactions tend to take place and they replace initial system.

    http://en.wikipedia.org/wiki/Orders_of_magnitude_(temperature [Broken])
    Last edited by a moderator: May 4, 2017
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