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: What is the relationship between $K_p$ and $K_c$ for a gas-phase reaction?

Answer: $K_p = K_c(RT)^{\Delta n}$, where $\Delta n$ is the change in moles of gas. Accounts for the pressure difference when converting between concentration and pressure equilibrium constants.

Flashcard 2: Identify the condition when $Q = K_c$ in a chemical reaction.

Answer: The system is at equilibrium. When the reaction quotient equals the equilibrium constant, rates are balanced.

Flashcard 3: 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 4: 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 5: 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 6: How do you determine the direction of the shift if $Q > K_c$?

Answer: The reaction shifts left towards reactants. When $Q > K_c$, there are too many products relative to equilibrium.

Flashcard 7: 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 8: 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 9: 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 10: 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 11: 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 12: 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 13: 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 14: 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 15: 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 16: 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 17: 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 18: 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 19: 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 20: 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 21: 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 22: 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 23: 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 24: How do you determine the direction of the shift if $Q > K_c$?

Answer: The reaction shifts left towards reactants. When $Q > K_c$, there are too many products relative to equilibrium.

Flashcard 25: 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 26: 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 27: 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 28: What is the relationship between $K_p$ and $K_c$ for a gas-phase reaction?

Answer: $K_p = K_c(RT)^{\Delta n}$, where $\Delta n$ is the change in moles of gas. Accounts for the pressure difference when converting between concentration and pressure equilibrium constants.

Flashcard 29: 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 30: What is the effect of diluting a solution at equilibrium?

Answer: Shifts towards the side with more moles of dissolved species. Dilution favors the side that produces more particles to maintain equilibrium.

Flashcard 31: 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 32: 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 33: 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 34: 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 35: 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 36: 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 37: Identify the effect of pressure decrease on equilibrium with equal moles of gas on both sides.

Answer: No change in equilibrium position. When $\Delta n = 0$, pressure changes don't affect equilibrium position.

Flashcard 38: In which direction will equilibrium shift when $K_c < Q$?

Answer: Shifts left, towards reactants. When $Q > K_c$, there are excess products, so the reaction proceeds backward.

Flashcard 39: 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 40: 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 41: 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 42: 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 43: 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 44: 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 45: Identify the condition when $Q = K_c$ in a chemical reaction.

Answer: The system is at equilibrium. When the reaction quotient equals the equilibrium constant, rates are balanced.

Flashcard 46: In which direction will equilibrium shift when $K_c < Q$?

Answer: Shifts left, towards reactants. When $Q > K_c$, there are excess products, so the reaction proceeds backward.

Flashcard 47: What is the relationship between $K_p$ and $K_c$ for a gas-phase reaction?

Answer: $K_p = K_c(RT)^{\Delta n}$, where $\Delta n$ is the change in moles of gas. Accounts for the pressure difference when converting between concentration and pressure equilibrium constants.

Flashcard 48: 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 49: 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 50: 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 51: 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 52: What happens to $K_c$ when the temperature is changed?

Answer: $K_c$ changes with temperature. Temperature is the only factor that changes the equilibrium constant value.

Flashcard 53: 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 54: 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 55: 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 56: 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 57: 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 58: What happens to $K_c$ when the temperature is changed?

Answer: $K_c$ changes with temperature. Temperature is the only factor that changes the equilibrium constant value.

Flashcard 59: 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 60: 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 61: What happens to $K_c$ when the temperature is changed?

Answer: $K_c$ changes with temperature. Temperature is the only factor that changes the equilibrium constant value.

Flashcard 62: 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 63: 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 64: 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 65: 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 66: Identify the condition when $Q = K_c$ in a chemical reaction.

Answer: The system is at equilibrium. When the reaction quotient equals the equilibrium constant, rates are balanced.

Flashcard 67: 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 68: 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 69: What happens to $K_c$ when the temperature is changed?

Answer: $K_c$ changes with temperature. Temperature is the only factor that changes the equilibrium constant value.

Flashcard 70: 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 71: 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 72: 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 73: 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 74: 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 75: 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 76: 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 77: Identify the condition when $Q = K_c$ in a chemical reaction.

Answer: The system is at equilibrium. When the reaction quotient equals the equilibrium constant, rates are balanced.

Flashcard 78: 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 79: 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 80: 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 81: 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 82: 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 83: 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 84: 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 85: What is the relationship between $K_p$ and $K_c$ for a gas-phase reaction?

Answer: $K_p = K_c(RT)^{\Delta n}$, where $\Delta n$ is the change in moles of gas. Accounts for the pressure difference when converting between concentration and pressure equilibrium constants.

Flashcard 86: What is the effect of diluting a solution at equilibrium?

Answer: Shifts towards the side with more moles of dissolved species. Dilution favors the side that produces more particles to maintain equilibrium.

Flashcard 87: 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 88: 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 89: 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 90: What is the effect of diluting a solution at equilibrium?

Answer: Shifts towards the side with more moles of dissolved species. Dilution favors the side that produces more particles to maintain equilibrium.

Flashcard 91: What is the effect of diluting a solution at equilibrium?

Answer: Shifts towards the side with more moles of dissolved species. Dilution favors the side that produces more particles to maintain equilibrium.

Flashcard 92: 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 93: 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 94: 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 95: 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 96: 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.