Calculating the Equilibrium Constant - AP Chemistry
Card 1 of 30
Identify the correct $K_c$ for $\text{CaCO}_3(s)\rightleftharpoons\text{CaO}(s)+\text{CO}_2(g)$.
Identify the correct $K_c$ for $\text{CaCO}_3(s)\rightleftharpoons\text{CaO}(s)+\text{CO}_2(g)$.
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$K_c=[\text{CO}_2]$. Solids omitted; only gaseous CO₂ appears in the expression.
$K_c=[\text{CO}_2]$. Solids omitted; only gaseous CO₂ appears in the expression.
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Identify the correct $K_c$ for $\text{N}_2(g)+3\text{H}_2(g)\rightleftharpoons^2\text{NH}_3(g)$.
Identify the correct $K_c$ for $\text{N}_2(g)+3\text{H}_2(g)\rightleftharpoons^2\text{NH}_3(g)$.
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$K_c=\frac{[\text{NH}_3]^2}{[\text{N}_2][\text{H}_2]^3}$. Products over reactants with coefficients: $2$ for NH₃, $3$ for H₂.
$K_c=\frac{[\text{NH}_3]^2}{[\text{N}_2][\text{H}_2]^3}$. Products over reactants with coefficients: $2$ for NH₃, $3$ for H₂.
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Which temperature unit must be used in $K_p=K_c(RT)^{\Delta n}$ calculations?
Which temperature unit must be used in $K_p=K_c(RT)^{\Delta n}$ calculations?
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$T$ must be in kelvin $(\text{K})$. Absolute temperature required for ideal gas calculations.
$T$ must be in kelvin $(\text{K})$. Absolute temperature required for ideal gas calculations.
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What is $\Delta n_{\text{gas}}$ for $K_p=K_c(RT)^{\Delta n_{\text{gas}}}$?
What is $\Delta n_{\text{gas}}$ for $K_p=K_c(RT)^{\Delta n_{\text{gas}}}$?
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$\Delta n_{\text{gas}}=\sum \nu_{\text{prod,gas}}-\sum \nu_{\text{react,gas}}$. Change in moles of gas: product coefficients minus reactant coefficients.
$\Delta n_{\text{gas}}=\sum \nu_{\text{prod,gas}}-\sum \nu_{\text{react,gas}}$. Change in moles of gas: product coefficients minus reactant coefficients.
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What is the value of $K$ for any reaction written as $X\rightleftharpoons X$?
What is the value of $K$ for any reaction written as $X\rightleftharpoons X$?
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$K=1$. Same species on both sides cancel out, leaving unity.
$K=1$. Same species on both sides cancel out, leaving unity.
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Which species are omitted from $K$ expressions: pure solids, pure liquids, gases, or aqueous solutes?
Which species are omitted from $K$ expressions: pure solids, pure liquids, gases, or aqueous solutes?
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Pure solids and pure liquids are omitted. Their activities equal 1, so they don't affect the equilibrium constant.
Pure solids and pure liquids are omitted. Their activities equal 1, so they don't affect the equilibrium constant.
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What is the general expression for $K_p$ for $aA+bB\rightleftharpoons cC+dD$ (gases)?
What is the general expression for $K_p$ for $aA+bB\rightleftharpoons cC+dD$ (gases)?
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$K_p=\frac{(P_C)^c(P_D)^d}{(P_A)^a(P_B)^b}$. Uses partial pressures instead of concentrations for gas-phase equilibria.
$K_p=\frac{(P_C)^c(P_D)^d}{(P_A)^a(P_B)^b}$. Uses partial pressures instead of concentrations for gas-phase equilibria.
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What is the general expression for $K_c$ for $aA+bB\rightleftharpoons cC+dD$?
What is the general expression for $K_c$ for $aA+bB\rightleftharpoons cC+dD$?
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$K_c=\frac{[C]^c[D]^d}{[A]^a[B]^b}$. Products over reactants, each raised to their stoichiometric coefficients.
$K_c=\frac{[C]^c[D]^d}{[A]^a[B]^b}$. Products over reactants, each raised to their stoichiometric coefficients.
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Calculate $K_c$ for $A\rightleftharpoons^2B$ if $[A]=0.50,\text{M}$ and $[B]=0.20,\text{M}$ at equilibrium.
Calculate $K_c$ for $A\rightleftharpoons^2B$ if $[A]=0.50,\text{M}$ and $[B]=0.20,\text{M}$ at equilibrium.
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$K_c=0.080$. $K_c = [B]^2/[A] = (0.20)^2/0.50 = 0.040/0.50 = 0.080$
$K_c=0.080$. $K_c = [B]^2/[A] = (0.20)^2/0.50 = 0.040/0.50 = 0.080$
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What is $K$ for the reaction if the given reaction has $K=3.0$ and all coefficients are doubled?
What is $K$ for the reaction if the given reaction has $K=3.0$ and all coefficients are doubled?
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$K_{\text{new}}=9.0$. Doubling coefficients squares $K$: $3.0^2 = 9.0$
$K_{\text{new}}=9.0$. Doubling coefficients squares $K$: $3.0^2 = 9.0$
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What is $K$ for the reverse reaction if $K=4.0\times10^{-3}$ for the forward reaction?
What is $K$ for the reverse reaction if $K=4.0\times10^{-3}$ for the forward reaction?
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$K_{\text{reverse}}=2.5\times10^2$. $K_{reverse} = 1 ÷ (4.0×10^{-3}) = 2.5×10^2$
$K_{\text{reverse}}=2.5\times10^2$. $K_{reverse} = 1 ÷ (4.0×10^{-3}) = 2.5×10^2$
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Find $K_c$ if $K_p=2.0$, $\Delta n_{\text{gas}}=-2$, $T=400,\text{K}$, and $R=0.0821$.
Find $K_c$ if $K_p=2.0$, $\Delta n_{\text{gas}}=-2$, $T=400,\text{K}$, and $R=0.0821$.
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$K_c=2.15\times10^3$. $K_c = 2.0 ÷ (0.0821 × 400)^{-2} = 2.0 × 1079 = 2.15×10^3$
$K_c=2.15\times10^3$. $K_c = 2.0 ÷ (0.0821 × 400)^{-2} = 2.0 × 1079 = 2.15×10^3$
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Find $K_p$ if $K_c=0.50$, $\Delta n_{\text{gas}}=1$, $T=300,\text{K}$, and $R=0.0821$.
Find $K_p$ if $K_c=0.50$, $\Delta n_{\text{gas}}=1$, $T=300,\text{K}$, and $R=0.0821$.
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$K_p=12.3$. $K_p = 0.50 × (0.0821 × 300)^1 = 0.50 × 24.63 = 12.3$
$K_p=12.3$. $K_p = 0.50 × (0.0821 × 300)^1 = 0.50 × 24.63 = 12.3$
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State the relationship between $K_p$ and $K_c$ using $\Delta n_{\text{gas}}$.
State the relationship between $K_p$ and $K_c$ using $\Delta n_{\text{gas}}$.
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$K_p=K_c(RT)^{\Delta n_{\text{gas}}}$. Relates pressure and concentration constants via ideal gas law.
$K_p=K_c(RT)^{\Delta n_{\text{gas}}}$. Relates pressure and concentration constants via ideal gas law.
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What is $K$ for an overall reaction made by adding reactions with constants $K_1$ and $K_2$?
What is $K$ for an overall reaction made by adding reactions with constants $K_1$ and $K_2$?
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$K_{\text{overall}}=K_1K_2$. When reactions add, their equilibrium constants multiply.
$K_{\text{overall}}=K_1K_2$. When reactions add, their equilibrium constants multiply.
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What happens to $K$ when all coefficients in the reaction are multiplied by $n$?
What happens to $K$ when all coefficients in the reaction are multiplied by $n$?
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$K_{\text{new}}=K^n$. Each concentration term gets raised to $n$, so $K$ is raised to $n$.
$K_{\text{new}}=K^n$. Each concentration term gets raised to $n$, so $K$ is raised to $n$.
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What happens to $K$ when the reaction is reversed?
What happens to $K$ when the reaction is reversed?
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$K_{\text{reverse}}=\frac{1}{K_{\text{forward}}}$. Reversing swaps products and reactants, inverting the fraction.
$K_{\text{reverse}}=\frac{1}{K_{\text{forward}}}$. Reversing swaps products and reactants, inverting the fraction.
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Calculate $K_p$ for $2A(g)\rightleftharpoons B(g)$ if $P_A=0.50,\text{atm}$ and $P_B=2.0,\text{atm}$ at equilibrium.
Calculate $K_p$ for $2A(g)\rightleftharpoons B(g)$ if $P_A=0.50,\text{atm}$ and $P_B=2.0,\text{atm}$ at equilibrium.
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$K_p=8.0$. $K_p = P_B/(P_A)^2 = 2.0/(0.50)^2 = 2.0/0.25 = 8.0$
$K_p=8.0$. $K_p = P_B/(P_A)^2 = 2.0/(0.50)^2 = 2.0/0.25 = 8.0$
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What is $\Delta n_{\text{gas}}$ for $2\text{SO}_2(g)+\text{O}_2(g)\rightleftharpoons^2\text{SO}_3(g)$?
What is $\Delta n_{\text{gas}}$ for $2\text{SO}_2(g)+\text{O}_2(g)\rightleftharpoons^2\text{SO}_3(g)$?
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$\Delta n_{\text{gas}}=-1$. $2$ moles gas products minus $3$ moles gas reactants equals $-1$.
$\Delta n_{\text{gas}}=-1$. $2$ moles gas products minus $3$ moles gas reactants equals $-1$.
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Identify the correct $K_c$ for $\text{CH}_3\text{COOH}(aq)\rightleftharpoons\text{H}^+(aq)+\text{CH}_3\text{COO}^-(aq)$.
Identify the correct $K_c$ for $\text{CH}_3\text{COOH}(aq)\rightleftharpoons\text{H}^+(aq)+\text{CH}_3\text{COO}^-(aq)$.
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$K_c=\frac{[\text{H}^+][\text{CH}_3\text{COO}^-]}{[\text{CH}_3\text{COOH}]}$. Weak acid dissociation: products over undissociated acid.
$K_c=\frac{[\text{H}^+][\text{CH}_3\text{COO}^-]}{[\text{CH}_3\text{COOH}]}$. Weak acid dissociation: products over undissociated acid.
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What is $K$ for the overall reaction if two steps have constants $K_1$ and $K_2$ and are added?
What is $K$ for the overall reaction if two steps have constants $K_1$ and $K_2$ and are added?
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$K_\text{overall}=K_1K_2$. When reactions add, equilibrium constants multiply.
$K_\text{overall}=K_1K_2$. When reactions add, equilibrium constants multiply.
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Calculate $K_c$ if at equilibrium $[A]=0.20,M$, $[B]=0.30,M$, $[C]=0.40,M$ for $A+B\rightleftharpoons C$.
Calculate $K_c$ if at equilibrium $[A]=0.20,M$, $[B]=0.30,M$, $[C]=0.40,M$ for $A+B\rightleftharpoons C$.
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$K_c=\frac{0.40}{(0.20)(0.30)}=6.7$. Substitute equilibrium concentrations into $K_c$ expression.
$K_c=\frac{0.40}{(0.20)(0.30)}=6.7$. Substitute equilibrium concentrations into $K_c$ expression.
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Which species are omitted from $K$ for a heterogeneous equilibrium involving pure solids and liquids?
Which species are omitted from $K$ for a heterogeneous equilibrium involving pure solids and liquids?
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Pure solids and pure liquids are omitted (activity $=1$). Their concentrations remain constant during reaction.
Pure solids and pure liquids are omitted (activity $=1$). Their concentrations remain constant during reaction.
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What is the effect on $K$ when a reaction is reversed?
What is the effect on $K$ when a reaction is reversed?
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$K_\text{rev}=\frac{1}{K}$. Reversing flips the fraction, giving the reciprocal.
$K_\text{rev}=\frac{1}{K}$. Reversing flips the fraction, giving the reciprocal.
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What is the relationship between $K_c$ and $K_p$ using $\Delta n$ and $R,T$?
What is the relationship between $K_c$ and $K_p$ using $\Delta n$ and $R,T$?
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$K_p=K_c(RT)^{\Delta n}$. Relates concentration and pressure equilibrium constants.
$K_p=K_c(RT)^{\Delta n}$. Relates concentration and pressure equilibrium constants.
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What is $\Delta n$ (used in $K_p=K_c(RT)^{\Delta n}$) for gas-phase equilibria?
What is $\Delta n$ (used in $K_p=K_c(RT)^{\Delta n}$) for gas-phase equilibria?
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$\Delta n=\text{mol gas products}-\text{mol gas reactants}$. Change in moles of gas from reactants to products.
$\Delta n=\text{mol gas products}-\text{mol gas reactants}$. Change in moles of gas from reactants to products.
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What is the equilibrium constant expression $K_c$ for $2NO_2(g)\rightleftharpoons N_2O_4(g)$?
What is the equilibrium constant expression $K_c$ for $2NO_2(g)\rightleftharpoons N_2O_4(g)$?
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$K_c=\frac{[N_2O_4]}{[NO_2]^2}$. Products over reactants with stoichiometric exponents.
$K_c=\frac{[N_2O_4]}{[NO_2]^2}$. Products over reactants with stoichiometric exponents.
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What is the equilibrium constant expression $K_p$ for $N_2(g)+3H_2(g)\rightleftharpoons 2NH_3(g)$?
What is the equilibrium constant expression $K_p$ for $N_2(g)+3H_2(g)\rightleftharpoons 2NH_3(g)$?
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$K_p=\frac{(P_{NH_3})^2}{P_{N_2}(P_{H_2})^3}$. Partial pressures raised to stoichiometric coefficients.
$K_p=\frac{(P_{NH_3})^2}{P_{N_2}(P_{H_2})^3}$. Partial pressures raised to stoichiometric coefficients.
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What is $K_c$ for $CaCO_3(s)\rightleftharpoons CaO(s)+CO_2(g)$?
What is $K_c$ for $CaCO_3(s)\rightleftharpoons CaO(s)+CO_2(g)$?
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$K_c=[CO_2]$. Solids omitted; only gas concentration appears.
$K_c=[CO_2]$. Solids omitted; only gas concentration appears.
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What is $K_p$ for $CaCO_3(s)\rightleftharpoons CaO(s)+CO_2(g)$?
What is $K_p$ for $CaCO_3(s)\rightleftharpoons CaO(s)+CO_2(g)$?
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$K_p=P_{CO_2}$. Solids omitted; only gas pressure appears.
$K_p=P_{CO_2}$. Solids omitted; only gas pressure appears.
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