20.3. Free Energy and Equilibrium http://www.ck12.org
FIGURE 20.5
Lesson Summary
- The reaction quotient can be compared to the equilibrium constant to determine which direction a reaction
will shift in order to reach equilibrium. - Gibbs free energy values can be used to determine equilibrium constants.
- Equilibrium constants can be used to calculate changes in Gibbs free energy.
- Equilibrium constants and Gibbs free energy values allow us to predict the extent to which reactants or
products will be favored once a reaction reaches equilibrium.
Lesson Review Questions
- What is the difference between the equilibrium constant and the reaction quotient?
- In which direction will the reaction proceed based on the three following conditions?
a. Q>Keq
b. Q<Keq
c. Q=Keq - What conditions does the notation∆G° imply? Explain the difference between∆G° and∆G.
- Define each value in the equation that relates∆G° and∆G.
- How can∆G° or Keqbe used to tell whether reactants or products are favored at equilibrium?
- Calculate∆G° for the process 2H 2 O(l) H 3 O+(aq) + OH−(aq) if the equilibrium constant at 25°C is
1 × 10 −^14. - Calculate∆G° and Keqfor the following reaction at 25°C: 2H 2 O(g) 2H 2 (g) + O 2 (g)
- Calculate the equilibrium constant for the following reaction at 25°C: 2O 3 (g) 3O 2 (g)
- Calculate∆G° for the ionization of acetic acid (CH 3 CO 2 H). The equilibrium constant for the following
reaction is 1.8× 10 −^5 :