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Homework Help: Gibbs Free energy

  1. Mar 30, 2008 #1
    1. The problem statement, all variables and given/known data
    CaCO3 <-> CaO + CO2
    At 900K, equilibrium pressure of CO2 is 0.0423 atm. Calculate Gibbs Free energy of Reaction and K.

    2. Relevant equations
    delta G = -RTlnK

    3. The attempt at a solution

    delta G = 5656.3 cal/mol
    K = 0.0423

    I have a feeling that this is incorrect
    Could someone confirm/clarify for me

  2. jcsd
  3. Apr 1, 2008 #2
    I'm not sure what the pressure has to do with it..
  4. Apr 1, 2008 #3


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    The equilibrium pressure of CO2 is directly connected to the [itex]\Delta G[/itex] of the reaction. If the forward reaction is strongly favored, the pressure is higher, and vice versa.
  5. Apr 1, 2008 #4
    ok, but does the pressure have anything to do with the calculations?

    delta G = [sum(delta G formation, products) - sum(delta G formation, reactants)]

    which can all be calculated from table values.

    Then the equation:

    delta G = -RTlnK can be used to find K

    is this correct?
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