Representations of Equilibrium - AP Chemistry
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How does the addition of a common ion affect the solubility of a salt?
How does the addition of a common ion affect the solubility of a salt?
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Solubility decreases due to the common ion effect. Increased concentration of a common ion shifts equilibrium toward the undissolved solid.
Solubility decreases due to the common ion effect. Increased concentration of a common ion shifts equilibrium toward the undissolved solid.
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What is the relationship between $K_{sp}$ and solubility?
What is the relationship between $K_{sp}$ and solubility?
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Higher $K_{sp}$ indicates greater solubility. Larger $K_{sp}$ values correspond to more soluble compounds at equilibrium.
Higher $K_{sp}$ indicates greater solubility. Larger $K_{sp}$ values correspond to more soluble compounds at equilibrium.
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What is the result of doubling the concentration of reactants at equilibrium?
What is the result of doubling the concentration of reactants at equilibrium?
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Equilibrium shifts right, producing more products. Increasing reactant concentration makes the forward reaction more favorable.
Equilibrium shifts right, producing more products. Increasing reactant concentration makes the forward reaction more favorable.
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What is the effect of adding more $N_2$ to the equilibrium $N_2 + 3H_2 \rightleftharpoons 2NH_3$?
What is the effect of adding more $N_2$ to the equilibrium $N_2 + 3H_2 \rightleftharpoons 2NH_3$?
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Equilibrium shifts right, producing more $NH_3$. Adding reactants increases their concentration, driving the reaction forward.
Equilibrium shifts right, producing more $NH_3$. Adding reactants increases their concentration, driving the reaction forward.
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Describe how a catalyst affects the position of equilibrium.
Describe how a catalyst affects the position of equilibrium.
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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.
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.
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What is the general effect of pressure increase on a gaseous equilibrium?
What is the general effect of pressure increase on a gaseous equilibrium?
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Shifts towards the side with fewer moles of gas. System responds to pressure increase by reducing the total number of gas molecules.
Shifts towards the side with fewer moles of gas. System responds to pressure increase by reducing the total number of gas molecules.
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What is the significance of $K_{eq} > 1$ for a chemical reaction?
What is the significance of $K_{eq} > 1$ for a chemical reaction?
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Products are favored at equilibrium. Large equilibrium constants mean the forward reaction is thermodynamically favorable.
Products are favored at equilibrium. Large equilibrium constants mean the forward reaction is thermodynamically favorable.
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How does $K_{eq}$ relate to the spontaneity of a reaction?
How does $K_{eq}$ relate to the spontaneity of a reaction?
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$K_{eq} > 1$ indicates a spontaneous reaction. Large equilibrium constants indicate thermodynamically favorable forward reactions.
$K_{eq} > 1$ indicates a spontaneous reaction. Large equilibrium constants indicate thermodynamically favorable forward reactions.
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What is the effect on equilibrium when a solid reactant is added?
What is the effect on equilibrium when a solid reactant is added?
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No effect on the equilibrium position. Solid concentrations don't appear in equilibrium expressions and don't affect position.
No effect on the equilibrium position. Solid concentrations don't appear in equilibrium expressions and don't affect position.
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What does a $K_{eq} = 1$ indicate about a reaction?
What does a $K_{eq} = 1$ indicate about a reaction?
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Neither reactants nor products are favored. Equal concentrations of reactants and products at equilibrium when $K_{eq} = 1$.
Neither reactants nor products are favored. Equal concentrations of reactants and products at equilibrium when $K_{eq} = 1$.
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Identify the principle that explains the effect of concentration changes on equilibrium.
Identify the principle that explains the effect of concentration changes on equilibrium.
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Le Chatelier's Principle. States that systems respond to stress by shifting to counteract the disturbance.
Le Chatelier's Principle. States that systems respond to stress by shifting to counteract the disturbance.
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State the effect of temperature increase on an exothermic reaction's equilibrium position.
State the effect of temperature increase on an exothermic reaction's equilibrium position.
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Shifts the equilibrium to the left (toward reactants). Heat is treated as a product in exothermic reactions, so adding heat shifts left.
Shifts the equilibrium to the left (toward reactants). Heat is treated as a product in exothermic reactions, so adding heat shifts left.
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What is the effect of adding more $H_2O$ to a gaseous equilibrium system?
What is the effect of adding more $H_2O$ to a gaseous equilibrium system?
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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.
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.
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What is the effect of increasing the temperature on $K_c$ for an exothermic reaction?
What is the effect of increasing the temperature on $K_c$ for an exothermic reaction?
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$K_c$ decreases. For exothermic reactions, higher temperature makes products less stable, decreasing $K_c$.
$K_c$ decreases. For exothermic reactions, higher temperature makes products less stable, decreasing $K_c$.
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How does the addition of a common ion affect the solubility of a salt?
How does the addition of a common ion affect the solubility of a salt?
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Solubility decreases due to the common ion effect. Increased concentration of a common ion shifts equilibrium toward the undissolved solid.
Solubility decreases due to the common ion effect. Increased concentration of a common ion shifts equilibrium toward the undissolved solid.
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State the effect of removing heat from an endothermic reaction.
State the effect of removing heat from an endothermic reaction.
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Shifts equilibrium to the left (toward reactants). Heat is treated as a reactant in endothermic reactions, so removing heat shifts left.
Shifts equilibrium to the left (toward reactants). Heat is treated as a reactant in endothermic reactions, so removing heat shifts left.
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What is the effect of decreasing volume on the equilibrium of a reaction with gases?
What is the effect of decreasing volume on the equilibrium of a reaction with gases?
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Equilibrium shifts toward the side with fewer moles of gas. System reduces stress by shifting to the side that occupies less volume.
Equilibrium shifts toward the side with fewer moles of gas. System reduces stress by shifting to the side that occupies less volume.
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How does the addition of a non-reactive gas affect the equilibrium position?
How does the addition of a non-reactive gas affect the equilibrium position?
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No effect on the equilibrium position. Inert gases don't participate in the reaction and don't change partial pressures.
No effect on the equilibrium position. Inert gases don't participate in the reaction and don't change partial pressures.
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What is the expression for $K_{sp}$ of $CaF_2$?
What is the expression for $K_{sp}$ of $CaF_2$?
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$K_{sp} = [Ca^{2+}][F^-]^2$. Products of ion concentrations raised to their stoichiometric coefficients for the dissolution.
$K_{sp} = [Ca^{2+}][F^-]^2$. Products of ion concentrations raised to their stoichiometric coefficients for the dissolution.
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What does a very small $K_c$ value indicate about a reaction?
What does a very small $K_c$ value indicate about a reaction?
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The reaction favors reactants at equilibrium. Small $K_c$ values mean the equilibrium position lies far to the left.
The reaction favors reactants at equilibrium. Small $K_c$ values mean the equilibrium position lies far to the left.
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Identify the factor that does not affect the value of $K_c$ for a reaction.
Identify the factor that does not affect the value of $K_c$ for a reaction.
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Pressure changes do not affect $K_c$.. Only temperature changes affect $K_c$; pressure and concentration changes don't.
Pressure changes do not affect $K_c$.. Only temperature changes affect $K_c$; pressure and concentration changes don't.
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What is the Le Chatelier's response to the removal of a product from the equilibrium mixture?
What is the Le Chatelier's response to the removal of a product from the equilibrium mixture?
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Equilibrium shifts right to produce more product. Removing products decreases $Q$, making the forward reaction more favorable.
Equilibrium shifts right to produce more product. Removing products decreases $Q$, making the forward reaction more favorable.
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What is the unit of $K_c$ for the reaction $N_2 + 3H_2 \rightleftharpoons 2NH_3$?
What is the unit of $K_c$ for the reaction $N_2 + 3H_2 \rightleftharpoons 2NH_3$?
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M^{-2}. Units are $\frac{M^2}{M \cdot M^3} = M^{-2}$ based on the concentration terms.
M^{-2}. Units are $\frac{M^2}{M \cdot M^3} = M^{-2}$ based on the concentration terms.
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What is the result of tripling the volume of a gaseous equilibrium system?
What is the result of tripling the volume of a gaseous equilibrium system?
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Shifts towards the side with more moles of gas. Increasing volume decreases pressure, favoring the side with more gas molecules.
Shifts towards the side with more moles of gas. Increasing volume decreases pressure, favoring the side with more gas molecules.
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What is $Q$ for the reaction $2A \rightleftharpoons B + C$ if $[A]=2$, $[B]=1$, $[C]=3$?
What is $Q$ for the reaction $2A \rightleftharpoons B + C$ if $[A]=2$, $[B]=1$, $[C]=3$?
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$Q = \frac{[B][C]}{[A]^2} = \frac{1 \times 3}{2^2} = 0.75$. Using $Q = \frac{[B][C]}{[A]^2}$ with the given concentrations.
$Q = \frac{[B][C]}{[A]^2} = \frac{1 \times 3}{2^2} = 0.75$. Using $Q = \frac{[B][C]}{[A]^2}$ with the given concentrations.
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What is the $K_c$ expression for $H_2 + I_2 \rightleftharpoons 2HI$?
What is the $K_c$ expression for $H_2 + I_2 \rightleftharpoons 2HI$?
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$K_c = \frac{[HI]^2}{[H_2][I_2]}$. Products raised to stoichiometric coefficients over reactants raised to their coefficients.
$K_c = \frac{[HI]^2}{[H_2][I_2]}$. Products raised to stoichiometric coefficients over reactants raised to their coefficients.
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What happens to equilibrium when an inert gas is added at constant volume?
What happens to equilibrium when an inert gas is added at constant volume?
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No change in equilibrium position. At constant volume, adding inert gas doesn't change partial pressures of reactants.
No change in equilibrium position. At constant volume, adding inert gas doesn't change partial pressures of reactants.
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State the effect of removing heat from an endothermic reaction.
State the effect of removing heat from an endothermic reaction.
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Shifts equilibrium to the left (toward reactants). Heat is treated as a reactant in endothermic reactions, so removing heat shifts left.
Shifts equilibrium to the left (toward reactants). Heat is treated as a reactant in endothermic reactions, so removing heat shifts left.
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What is the expression for $K_{sp}$ of $CaF_2$?
What is the expression for $K_{sp}$ of $CaF_2$?
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$K_{sp} = [Ca^{2+}][F^-]^2$. Products of ion concentrations raised to their stoichiometric coefficients for the dissolution.
$K_{sp} = [Ca^{2+}][F^-]^2$. Products of ion concentrations raised to their stoichiometric coefficients for the dissolution.
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What does a very small $K_c$ value indicate about a reaction?
What does a very small $K_c$ value indicate about a reaction?
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The reaction favors reactants at equilibrium. Small $K_c$ values mean the equilibrium position lies far to the left.
The reaction favors reactants at equilibrium. Small $K_c$ values mean the equilibrium position lies far to the left.
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