Unit 9.3: Gibbs Free Energy and Thermodynamic Favorability
Use the given value of ∆G to determine if a system is thermodynamically
favorable at a certain temperature.
- If ∆G = -25 kJ at 298 K, is the reaction spontaneous? Why?
- What does it mean if ∆G is positive for a reaction?
Calculate the free energy of a system using ∆G°rxn = ∑∆Gf°prod -
∑∆Gf°react.
-
Calculate ∆G°rxn for the formation of H₂O(l) from H₂(g) and O₂(g)
given ∆Gf° values.
-
Why are ∆Gf° values for elements in their standard state equal to
zero?
Determine thermodynamic favorability using ∆G = ∆H - T∆S at a given
temperature.
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Explain why a reaction with ∆H < 0 and ∆S > 0 is always favorable.
-
At what temperature might a reaction with ∆H > 0 and ∆S > 0 become
favorable?
Assess thermodynamic favorability based on relative magnitudes (signs)
of ∆H and ∆S under high and low temperatures.
-
Which sign combination of ∆H and ∆S always leads to a favorable
reaction?
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How does temperature influence reactions with ∆H > 0 and ∆S > 0?