AP Chemistry Flashcards: Representations Of Equilibrium

What this deck covers

This deck focuses on Representations Of 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: How does the addition of a common ion affect the solubility of a salt?

Answer: Solubility decreases due to the common ion effect. Increased concentration of a common ion shifts equilibrium toward the undissolved solid.

Flashcard 2: What is the relationship between $K_{sp}$ and solubility?

Answer: Higher $K_{sp}$ indicates greater solubility. Larger $K_{sp}$ values correspond to more soluble compounds at equilibrium.

Flashcard 3: What is the result of doubling the concentration of reactants at equilibrium?

Answer: Equilibrium shifts right, producing more products. Increasing reactant concentration makes the forward reaction more favorable.

Flashcard 4: What is the effect of adding more $N_2$ to the equilibrium $N_2 + 3H_2 \rightleftharpoons 2NH_3$?

Answer: Equilibrium shifts right, producing more $NH_3$. Adding reactants increases their concentration, driving the reaction forward.

Flashcard 5: Describe how a catalyst affects the position of equilibrium.

Answer: A catalyst does not affect the position of equilibrium. Catalysts only speed up the rate of reaching equilibrium but don't change the final position.

Flashcard 6: What is the general effect of pressure increase on a gaseous equilibrium?

Answer: Shifts towards the side with fewer moles of gas. System responds to pressure increase by reducing the total number of gas molecules.

Flashcard 7: What is the significance of $K_{eq} > 1$ for a chemical reaction?

Answer: Products are favored at equilibrium. Large equilibrium constants mean the forward reaction is thermodynamically favorable.

Flashcard 8: How does $K_{eq}$ relate to the spontaneity of a reaction?

Answer: $K_{eq} > 1$ indicates a spontaneous reaction. Large equilibrium constants indicate thermodynamically favorable forward reactions.

Flashcard 9: What is the effect on equilibrium when a solid reactant is added?

Answer: No effect on the equilibrium position. Solid concentrations don't appear in equilibrium expressions and don't affect position.

Flashcard 10: What does a $K_{eq} = 1$ indicate about a reaction?

Answer: Neither reactants nor products are favored. Equal concentrations of reactants and products at equilibrium when $K_{eq} = 1$.

Flashcard 11: Identify the principle that explains the effect of concentration changes on equilibrium.

Answer: Le Chatelier's Principle. States that systems respond to stress by shifting to counteract the disturbance.

Flashcard 12: State the effect of temperature increase on an exothermic reaction's equilibrium position.

Answer: Shifts the equilibrium to the left (toward reactants). Heat is treated as a product in exothermic reactions, so adding heat shifts left.

Flashcard 13: What is the effect of adding more $H_2O$ to a gaseous equilibrium system?

Answer: No effect if $H_2O$ is not a reactant or product in gaseous form. Liquid water doesn't affect gas-phase equilibria unless it participates as a gas.

Flashcard 14: What is the effect of increasing the temperature on $K_c$ for an exothermic reaction?

Answer: $K_c$ decreases. For exothermic reactions, higher temperature makes products less stable, decreasing $K_c$.

Flashcard 15: How does the addition of a common ion affect the solubility of a salt?

Answer: Solubility decreases due to the common ion effect. Increased concentration of a common ion shifts equilibrium toward the undissolved solid.

Flashcard 16: State the effect of removing heat from an endothermic reaction.

Answer: Shifts equilibrium to the left (toward reactants). Heat is treated as a reactant in endothermic reactions, so removing heat shifts left.

Flashcard 17: What is the effect of decreasing volume on the equilibrium of a reaction with gases?

Answer: Equilibrium shifts toward the side with fewer moles of gas. System reduces stress by shifting to the side that occupies less volume.

Flashcard 18: How does the addition of a non-reactive gas affect the equilibrium position?

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

Flashcard 19: What is the expression for $K_{sp}$ of $CaF_2$?

Answer: $K_{sp} = [Ca^{2+}][F^-]^2$. Products of ion concentrations raised to their stoichiometric coefficients for the dissolution.

Flashcard 20: What does a very small $K_c$ value indicate about a reaction?

Answer: The reaction favors reactants at equilibrium. Small $K_c$ values mean the equilibrium position lies far to the left.

Flashcard 21: Identify the factor that does not affect the value of $K_c$ for a reaction.

Answer: Pressure changes do not affect $K_c$.. Only temperature changes affect $K_c$; pressure and concentration changes don't.

Flashcard 22: What is the Le Chatelier's response to the removal of a product from the equilibrium mixture?

Answer: Equilibrium shifts right to produce more product. Removing products decreases $Q$, making the forward reaction more favorable.

Flashcard 23: What is the unit of $K_c$ for the reaction $N_2 + 3H_2 \rightleftharpoons 2NH_3$?

Answer: M^{-2}. Units are $\frac{M^2}{M \cdot M^3} = M^{-2}$ based on the concentration terms.

Flashcard 24: What is the result of tripling the volume of a gaseous equilibrium system?

Answer: Shifts towards the side with more moles of gas. Increasing volume decreases pressure, favoring the side with more gas molecules.

Flashcard 25: What is $Q$ for the reaction $2A \rightleftharpoons B + C$ if $[A]=2$, $[B]=1$, $[C]=3$?

Answer: $Q = \frac{[B][C]}{[A]^2} = \frac{1 \times 3}{2^2} = 0.75$. Using $Q = \frac{[B][C]}{[A]^2}$ with the given concentrations.

Flashcard 26: What is the $K_c$ expression for $H_2 + I_2 \rightleftharpoons 2HI$?

Answer: $K_c = \frac{[HI]^2}{[H_2][I_2]}$. Products raised to stoichiometric coefficients over reactants raised to their coefficients.

Flashcard 27: What happens to equilibrium when an inert gas is added at constant volume?

Answer: No change in equilibrium position. At constant volume, adding inert gas doesn't change partial pressures of reactants.

Flashcard 28: State the effect of removing heat from an endothermic reaction.

Answer: Shifts equilibrium to the left (toward reactants). Heat is treated as a reactant in endothermic reactions, so removing heat shifts left.

Flashcard 29: What is the expression for $K_{sp}$ of $CaF_2$?

Answer: $K_{sp} = [Ca^{2+}][F^-]^2$. Products of ion concentrations raised to their stoichiometric coefficients for the dissolution.

Flashcard 30: What does a very small $K_c$ value indicate about a reaction?

Answer: The reaction favors reactants at equilibrium. Small $K_c$ values mean the equilibrium position lies far to the left.