AP Chemistry Flashcards: Free Energy And Equilibrium

What this deck covers

This deck focuses on Free Energy And Equilibrium, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: What is the term for the energy required to break bonds in reactants?

Answer: Bond dissociation energy. Energy input needed to break existing chemical bonds in reactants.

Flashcard 2: What does the term 'enthalpy' refer to in thermodynamics?

Answer: The total heat content of a system. Enthalpy represents the total energy stored in chemical bonds.

Flashcard 3: What does a positive $\triangle G$ indicate about a reaction?

Answer: The reaction is non-spontaneous. Positive $\triangle G$ means external energy is required for the process to occur.

Flashcard 4: What is the effect of a common ion on the solubility of a salt?

Answer: Decreases solubility. Common ion effect shifts equilibrium by Le Châtelier's principle.

Flashcard 5: What is the significance of $\triangle G = 0$?

Answer: The system is at equilibrium. At equilibrium, forward and reverse reaction rates are equal.

Flashcard 6: What condition is necessary for a reaction to be at equilibrium in terms of $Q$ and $K$?

Answer: $Q = K$. At equilibrium, the reaction quotient equals the equilibrium constant.

Flashcard 7: Identify the units for Gibbs free energy change, $\triangle G$.

Answer: Joules (J). Energy units match the dimensions of enthalpy and entropy terms.

Flashcard 8: What is the significance of the equilibrium constant $K$ being less than 1?

Answer: Reactants are favored at equilibrium. Small $K$ values indicate equilibrium lies toward the reactant side.

Flashcard 9: What happens to the equilibrium constant $K$ as temperature increases for an endothermic reaction?

Answer: $K$ increases. Higher temperature favors endothermic reactions, increasing $K$.

Flashcard 10: State the equation relating Gibbs free energy and reaction quotient $Q$.

Answer: $\triangle G = \triangle G^\text{°} + RT \text{ln}Q$. This equation relates free energy to reaction progress via quotient $Q$.

Flashcard 11: Identify the condition under which a reaction is at dynamic equilibrium.

Answer: Rate of forward and reverse reactions are equal. Dynamic equilibrium means constant concentrations with ongoing reactions.

Flashcard 12: What is the effect of increasing volume on the equilibrium of a gaseous reaction?

Answer: Shifts toward more moles of gas. Larger volume favors the side with more gas molecules.

Flashcard 13: What happens to the equilibrium constant $K$ as temperature increases for an exothermic reaction?

Answer: $K$ decreases. Higher temperature disfavors exothermic reactions, reducing $K$.

Flashcard 14: What is the effect of adding a catalyst on the equilibrium position?

Answer: No effect on equilibrium position. Catalysts speed up both forward and reverse reactions equally.

Flashcard 15: State the relationship between $\triangle G^\text{°}$ and $K$ for a reaction at equilibrium.

Answer: $\triangle G^\text{°} = -RT \text{ln}K$. Standard free energy change relates directly to equilibrium constant.

Flashcard 16: What is the effect of increasing pressure on the equilibrium of a gaseous reaction?

Answer: Shifts toward fewer moles of gas. Higher pressure favors the side with fewer gas molecules.

Flashcard 17: What is the effect of decreasing temperature on an exothermic reaction’s equilibrium position?

Answer: Shifts to the right (toward products). Lower temperature favors the exothermic direction per Le Châtelier's principle.

Flashcard 18: How does the addition of an inert gas at constant volume affect equilibrium?

Answer: No effect on equilibrium. Inert gases don't participate and don't change partial pressures.

Flashcard 19: What does Le Châtelier's principle predict?

Answer: How a system at equilibrium responds to changes. Le Châtelier's principle describes equilibrium shifts to counteract disturbances.

Flashcard 20: What is the effect of increasing temperature on an exothermic reaction's equilibrium position?

Answer: Shifts to the left (toward reactants). Higher temperature opposes the exothermic direction per Le Châtelier's principle.

Flashcard 21: What does the term 'entropy' refer to in thermodynamics?

Answer: The measure of disorder or randomness. Entropy quantifies the number of possible microstates in a system.

Flashcard 22: What is the effect of increasing temperature on an endothermic reaction's equilibrium position?

Answer: Shifts to the right (toward products). Higher temperature favors the endothermic direction according to Le Châtelier's principle.

Flashcard 23: Which term describes a reaction with $\triangle H > 0$?

Answer: Endothermic. Positive enthalpy change indicates heat is absorbed from surroundings.

Flashcard 24: What is the meaning of Gibbs free energy being state function?

Answer: Depends only on initial and final states. State functions are path-independent, only depending on endpoints.

Flashcard 25: State the equation relating $\triangle G$ and equilibrium constant $K$.

Answer: $\triangle G = -RT \text{ln}K$. This equation connects thermodynamics ($\triangle G$) to kinetics ($K$).

Flashcard 26: What is the significance of the equilibrium constant $K$ being greater than 1?

Answer: Products are favored at equilibrium. Large $K$ values indicate equilibrium lies toward the product side.

Flashcard 27: Which term describes a reaction with $\triangle H < 0$?

Answer: Exothermic. Negative enthalpy change indicates heat is released to surroundings.

Flashcard 28: Determine the sign of $\triangle G$ for a process at equilibrium.

Answer: $\triangle G = 0$. At equilibrium, there is no net change in free energy.

Flashcard 29: Which term describes a reaction with $\triangle H > 0$?

Answer: Endothermic. Positive enthalpy change indicates heat is absorbed from surroundings.

Flashcard 30: Which term describes a reaction with $\triangle H > 0$?

Answer: Endothermic. Positive enthalpy change indicates heat is absorbed from surroundings.