Equilibrium Constant (Kc)

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Calculate the equilibrium constant (Kc) for a chemical reaction: aA + bB ⇌ cC + dD, based on molar concentrations.

Reaction Conditions

Temperature (T)

Reactants (Left Side)

Species A

Conc. [X] (M)

Coeff.

Species B

Conc. [X] (M)

Coeff.

Products (Right Side)

Species C

Conc. [X] (M)

Coeff.

Species D

Conc. [X] (M)

Coeff.

Calculation Results

Enter concentrations and coefficients to calculate Kc

About this calculator

Overview

The equilibrium constant (Kc) expresses the ratio of product concentrations to reactant concentrations at equilibrium, each raised to the power of their stoichiometric coefficients.

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Pro Tips

Solids and pure liquids are excluded from the Kc expression (their activity is 1).
Concentrations must be in Molarity (mol/L).
Formula: Kc = ([C]^c · [D]^d) / ([A]^a · [B]^b).
Kp = (P_C^c · P_D^d) / (P_A^a · P_B^b) for gas-phase reactions.
Temperature changes can alter Kc values.
Kc is dimensionless when all coefficients are equal.

Fun Facts

"If Kc >> 1, the reaction favors products (equilibrium lies to the right)."
"If Kc << 1, the reaction favors reactants (equilibrium lies to the left)."
"Kc depends only on the reaction and temperature, not on initial concentrations."
"Kp is used for gas-phase reactions (in terms of partial pressures)."
"Kc = Kp / (RT)^Δn, where Δn is the change in moles of gas."
"Le Chatelier's principle explains how changing conditions affects equilibrium position."
"Catalysts speed up reactions but don't change the equilibrium constant."

Formula: Kc = ([C]ᶜ[D]ᵈ) / ([A]ᵃ[B]ᵇ)