AP Chemistry Flashcards: Free Energy and Equilibrium
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 11 cards to help you master important concepts.
What is the primary equation that relates standard free energy change (ΔG°) to the equilibrium constant (K)?
The relationship is given by the equation ΔG° = −RT ln K, where R is the ideal gas constant and T is the temperature in Kelvin.
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What is the primary equation that relates standard free energy change (ΔG°) to the equilibrium constant (K)?
The relationship is given by the equation ΔG° = −RT ln K, where R is the ideal gas constant and T is the temperature in Kelvin.
What three variables are interconnected when determining if a process is thermodynamically favored?
The thermodynamic favorability of a process is determined by the relationships between the equilibrium constant (K), standard free energy (ΔG°), and temperature (T).
If a process has a negative standard free energy change (ΔG° < 0), what does this imply about the value of K?
A process with ΔG° < 0 is thermodynamically favored, which means its equilibrium constant K will be greater than 1.
What does an equilibrium constant (K) value of greater than 1 signify?
A K value greater than 1 (K > 1) signifies that the products are favored at equilibrium.
What does the term 'thermodynamically favored' mean under standard conditions?
It means the standard free energy change is negative (ΔG° < 0) and that the products are favored at equilibrium, resulting in an equilibrium constant K > 1.
For a reaction where the magnitude of ΔG° is much larger than the value of RT, what can be inferred about its equilibrium state?
When |ΔG°| is much larger than RT, the equilibrium constant K deviates strongly from 1, meaning the reaction will go nearly to completion or hardly proceed at all.
How can you rearrange the free energy equation to solve for the equilibrium constant, K?
The equilibrium constant can be calculated directly using the equation K = e^−ΔG°/RT.
Summarize the qualitative relationship between the sign of ΔG° and which side of a reaction is favored.
Processes with ΔG° < 0 favor products, while those with ΔG° > 0 favor reactants at equilibrium.
A reaction at standard conditions has a ΔG° value very close to zero. What can you predict about its equilibrium constant, K?
When ΔG° is near zero, the equilibrium constant K will be close to 1, indicating significant amounts of both reactants and products at equilibrium.
What does an equilibrium constant (K) value of less than 1 signify?
A K value less than 1 (K < 1) signifies that the reactants are favored at equilibrium.
If a process has a positive standard free energy change (ΔG° > 0), what does this imply about the value of K?
A process with ΔG° > 0 is not thermodynamically favored, meaning its equilibrium constant K will be less than 1, and reactants are favored.