This video is about Thermodynamics and explains in details the relationship between Gibbs Free Energy, Pressure and Equilibrium. In this video also you will learn about the relationship between the equilibrium constant K and Temperature and Standard Free Energy. After watching this video, you should be able to:

  • Understand the Standard Free Energy Change and how it is measured.
  • Be able to calculate the Standard Free Energy Change by three different methods:
    • By using ∆Go= ∆Ho – T∆So
    • By manipulating known equations, as in Hess’s Law problems for ∆Ho
    • By using standard free energy of formation
  • Predict the spontaneity of chemical reactions from calculated standard free energy values.
  • Understand that the more negative the value for ∆Go, the farther to the right the reaction will proceed in order to achieve equilibrium

The Dependence of Free Energy on Pressure

  • Calculate ∆G at pressures other than 1 atmosphere using ∆G = ∆Go + RT ln(Q).

Free Energy and Equilibrium

  • Interconvert between K and ∆G.
  • Recognize that equilibrium point occurs at the lowest value of free energy available to the reaction system.
  • Recognize that at equilibrium, ∆G = 0 and Q = K therefore ∆Go = -RTln(K)
  • Show the temperature dependence of K using ∆Go = -RT ln(K) = ∆Ho – T∆So.
  • Interpret ln(K) versus 1/T graph and how it is used to calculate ∆Ho and ∆So

One thought on “Free Energy, Pressure & Equilibrium

  • October 27, 2017 at 3:21 AM

    Dr. Hayek,

    On this video at time 2:24 you said the delta G of reaction is 2GNH3 – 2GN2 – 3GH2. But I actually think its 2GNH3 – (2GN2+3GH2). I think it’s the latter because since Delta G is equal to the sum of products minus sum of reactants, thus you should sum 2GN2 and 3GH2. If I’m misunderstanding something, please let me know!

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