Reaction Quotient and Le Chatelier's Principle - AP Chemistry
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What happens to $K_c$ in an exothermic reaction if temperature decreases?
What happens to $K_c$ in an exothermic reaction if temperature decreases?
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$K_c$ increases with a decrease in temperature. Lower temperature favors exothermic reactions, increasing $K_c$.
$K_c$ increases with a decrease in temperature. Lower temperature favors exothermic reactions, increasing $K_c$.
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How does temperature decrease affect $K_c$ in endothermic reactions?
How does temperature decrease affect $K_c$ in endothermic reactions?
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$K_c$ decreases with a decrease in temperature. Lower temperature opposes endothermic reactions, decreasing $K_c$.
$K_c$ decreases with a decrease in temperature. Lower temperature opposes endothermic reactions, decreasing $K_c$.
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What effect does temperature have on $K_c$ for endothermic reactions?
What effect does temperature have on $K_c$ for endothermic reactions?
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$K_c$ increases with an increase in temperature. Higher temperature favors endothermic reactions, increasing $K_c$.
$K_c$ increases with an increase in temperature. Higher temperature favors endothermic reactions, increasing $K_c$.
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Define the reaction quotient, $Q_c$.
Define the reaction quotient, $Q_c$.
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The ratio of product concentrations to reactant concentrations at any point. Measures current concentration ratio, not necessarily at equilibrium.
The ratio of product concentrations to reactant concentrations at any point. Measures current concentration ratio, not necessarily at equilibrium.
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What does $Q_c > K_c$ suggest about reaction direction?
What does $Q_c > K_c$ suggest about reaction direction?
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The reaction will proceed in the reverse direction. When $Q_c > K_c$, excess products convert back to reactants.
The reaction will proceed in the reverse direction. When $Q_c > K_c$, excess products convert back to reactants.
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What happens when $Q_c$ is less than $K_c$?
What happens when $Q_c$ is less than $K_c$?
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The reaction proceeds forward to reach equilibrium. When $Q_c < K_c$, forward reaction proceeds to reach equilibrium.
The reaction proceeds forward to reach equilibrium. When $Q_c < K_c$, forward reaction proceeds to reach equilibrium.
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Calculate $Q_c$ for a reaction if $[A] = 1.0$, $[B] = 2.0$, $[C] = 1.5$ for $A + B \rightleftharpoons C$.
Calculate $Q_c$ for a reaction if $[A] = 1.0$, $[B] = 2.0$, $[C] = 1.5$ for $A + B \rightleftharpoons C$.
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$Q_c = \frac{[C]}{[A][B]} = \frac{1.5}{1.0 \times 2.0} = 0.75$. Apply the $Q_c$ formula using the given concentration values.
$Q_c = \frac{[C]}{[A][B]} = \frac{1.5}{1.0 \times 2.0} = 0.75$. Apply the $Q_c$ formula using the given concentration values.
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Which direction does equilibrium shift when a reactant concentration decreases?
Which direction does equilibrium shift when a reactant concentration decreases?
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The equilibrium shifts to the left, forming more reactants. System compensates by producing more of the depleted reactant.
The equilibrium shifts to the left, forming more reactants. System compensates by producing more of the depleted reactant.
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State the expression for $Q_c$ for $3A \rightleftharpoons 2B + C$.
State the expression for $Q_c$ for $3A \rightleftharpoons 2B + C$.
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$Q_c = \frac{[B]^2[C]}{[A]^3}$. Products in numerator, reactants in denominator with stoichiometric coefficients.
$Q_c = \frac{[B]^2[C]}{[A]^3}$. Products in numerator, reactants in denominator with stoichiometric coefficients.
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How does removing a reactant affect the position of equilibrium?
How does removing a reactant affect the position of equilibrium?
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The equilibrium shifts to the left, forming more reactants. System produces more reactant to replace what was removed.
The equilibrium shifts to the left, forming more reactants. System produces more reactant to replace what was removed.
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How does adding an inert gas at constant volume affect equilibrium?
How does adding an inert gas at constant volume affect equilibrium?
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There is no effect on the position of equilibrium. Inert gas doesn't change partial pressures of reactants or products.
There is no effect on the position of equilibrium. Inert gas doesn't change partial pressures of reactants or products.
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How does increasing the concentration of a reactant affect equilibrium?
How does increasing the concentration of a reactant affect equilibrium?
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The equilibrium shifts to the right, forming more products. System responds by consuming the excess reactant to form products.
The equilibrium shifts to the right, forming more products. System responds by consuming the excess reactant to form products.
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What does $Q_c = K_c$ signify?
What does $Q_c = K_c$ signify?
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The system is at equilibrium. When $Q_c$ equals $K_c$, forward and reverse reaction rates are equal.
The system is at equilibrium. When $Q_c$ equals $K_c$, forward and reverse reaction rates are equal.
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What does $Q_c < K_c$ indicate about reaction direction?
What does $Q_c < K_c$ indicate about reaction direction?
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The reaction will proceed forward to reach equilibrium. When $Q_c < K_c$, more products must form to reach equilibrium.
The reaction will proceed forward to reach equilibrium. When $Q_c < K_c$, more products must form to reach equilibrium.
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State the reaction quotient expression for $2A + B \rightleftharpoons 3C + D$.
State the reaction quotient expression for $2A + B \rightleftharpoons 3C + D$.
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$Q_c = \frac{[C]^3[D]}{[A]^2[B]}$. Products in numerator with coefficients as exponents, reactants in denominator.
$Q_c = \frac{[C]^3[D]}{[A]^2[B]}$. Products in numerator with coefficients as exponents, reactants in denominator.
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What happens to equilibrium when an aqueous solution is diluted?
What happens to equilibrium when an aqueous solution is diluted?
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The equilibrium shifts to the side with more solute particles. Dilution favors the side that produces more dissolved particles.
The equilibrium shifts to the side with more solute particles. Dilution favors the side that produces more dissolved particles.
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Identify the change in equilibrium with an increase in product pressure.
Identify the change in equilibrium with an increase in product pressure.
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The equilibrium shifts to the left, forming more reactants. Increased product concentration drives the reaction backward.
The equilibrium shifts to the left, forming more reactants. Increased product concentration drives the reaction backward.
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What is the effect of temperature increase on an endothermic reaction at equilibrium?
What is the effect of temperature increase on an endothermic reaction at equilibrium?
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The equilibrium shifts to the right, favoring product formation. Higher temperature favors the endothermic direction (forward).
The equilibrium shifts to the right, favoring product formation. Higher temperature favors the endothermic direction (forward).
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What happens to $K_c$ with temperature change in an exothermic reaction?
What happens to $K_c$ with temperature change in an exothermic reaction?
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$K_c$ decreases with an increase in temperature. Higher temperature opposes exothermic reactions, decreasing $K_c$.
$K_c$ decreases with an increase in temperature. Higher temperature opposes exothermic reactions, decreasing $K_c$.
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Calculate $Q_c$ for $A + B \rightleftharpoons 2C$ if $[A] = 0.5$, $[B] = 0.5$, $[C] = 0.1$.
Calculate $Q_c$ for $A + B \rightleftharpoons 2C$ if $[A] = 0.5$, $[B] = 0.5$, $[C] = 0.1$.
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$Q_c = \frac{[C]^2}{[A][B]} = \frac{0.1^2}{0.5 \times 0.5} = 0.04$. Substitute given concentrations into the $Q_c$ formula.
$Q_c = \frac{[C]^2}{[A][B]} = \frac{0.1^2}{0.5 \times 0.5} = 0.04$. Substitute given concentrations into the $Q_c$ formula.
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How does decreasing temperature affect an exothermic reaction at equilibrium?
How does decreasing temperature affect an exothermic reaction at equilibrium?
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The equilibrium shifts to the right, favoring product formation. Lower temperature favors the exothermic direction (forward).
The equilibrium shifts to the right, favoring product formation. Lower temperature favors the exothermic direction (forward).
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What is the value of $Q_c$ if $[A] = 2$, $[B] = 3$, $[C] = 1$, $[D] = 4$ for $A + 2B \rightleftharpoons C + D$?
What is the value of $Q_c$ if $[A] = 2$, $[B] = 3$, $[C] = 1$, $[D] = 4$ for $A + 2B \rightleftharpoons C + D$?
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$Q_c = \frac{[C][D]}{[A][B]^2} = \frac{1 \times 4}{2 \times 3^2} = \frac{2}{9}$. Substitute concentrations into $Q_c$ expression and calculate.
$Q_c = \frac{[C][D]}{[A][B]^2} = \frac{1 \times 4}{2 \times 3^2} = \frac{2}{9}$. Substitute concentrations into $Q_c$ expression and calculate.
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What is the effect of temperature decrease on the $K_c$ of an endothermic reaction?
What is the effect of temperature decrease on the $K_c$ of an endothermic reaction?
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$K_c$ decreases with a decrease in temperature. Lower temperature opposes endothermic reactions, decreasing $K_c$.
$K_c$ decreases with a decrease in temperature. Lower temperature opposes endothermic reactions, decreasing $K_c$.
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What is the effect of temperature increase on the equilibrium constant for exothermic reactions?
What is the effect of temperature increase on the equilibrium constant for exothermic reactions?
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The equilibrium constant, $K_c$, decreases. Higher temperature opposes exothermic reactions, reducing $K_c$.
The equilibrium constant, $K_c$, decreases. Higher temperature opposes exothermic reactions, reducing $K_c$.
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What is the effect of increasing volume on a gaseous equilibrium?
What is the effect of increasing volume on a gaseous equilibrium?
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The equilibrium shifts to the side with more moles of gas. Increased volume decreases pressure, favoring more gas molecules.
The equilibrium shifts to the side with more moles of gas. Increased volume decreases pressure, favoring more gas molecules.
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How does the addition of an inert gas at constant pressure affect equilibrium?
How does the addition of an inert gas at constant pressure affect equilibrium?
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It changes the equilibrium position depending on moles of gas. At constant pressure, inert gas causes volume expansion affecting equilibrium.
It changes the equilibrium position depending on moles of gas. At constant pressure, inert gas causes volume expansion affecting equilibrium.
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What happens when $Q_c$ is less than $K_c$?
What happens when $Q_c$ is less than $K_c$?
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The reaction proceeds forward to reach equilibrium. When $Q_c < K_c$, forward reaction proceeds to reach equilibrium.
The reaction proceeds forward to reach equilibrium. When $Q_c < K_c$, forward reaction proceeds to reach equilibrium.
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State what happens to equilibrium if a catalyst is added.
State what happens to equilibrium if a catalyst is added.
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The rate increases, but equilibrium position is unchanged. Catalysts affect kinetics but not the equilibrium position.
The rate increases, but equilibrium position is unchanged. Catalysts affect kinetics but not the equilibrium position.
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Calculate $Q_c$ for $2A \rightleftharpoons B$ if $[A] = 0.3$, $[B] = 0.2$.
Calculate $Q_c$ for $2A \rightleftharpoons B$ if $[A] = 0.3$, $[B] = 0.2$.
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$Q_c = \frac{[B]}{[A]^2} = \frac{0.2}{0.3^2} = 2.22$. Substitute the given concentrations into the $Q_c$ expression.
$Q_c = \frac{[B]}{[A]^2} = \frac{0.2}{0.3^2} = 2.22$. Substitute the given concentrations into the $Q_c$ expression.
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What defines the direction of shift when pressure is increased in a gaseous reaction?
What defines the direction of shift when pressure is increased in a gaseous reaction?
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Shifts to the side with fewer moles of gas. Higher pressure favors the side with fewer gas molecules.
Shifts to the side with fewer moles of gas. Higher pressure favors the side with fewer gas molecules.
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