How Do You Calculate Keq

Equilibrium Constant Formula:

\[ K_{eq} = \frac{[Products]}{[Reactants]} \]

Equilibrium Constant (K_eq):

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1. What is the Equilibrium Constant?

The equilibrium constant (K_eq) is a quantitative measure of the position of equilibrium in a chemical reaction. It represents the ratio of product concentrations to reactant concentrations at equilibrium, with each concentration raised to the power of its stoichiometric coefficient.

2. How Does the Calculator Work?

The calculator uses the equilibrium constant formula:

\[ K_{eq} = \frac{[Products]}{[Reactants]} \]

Where:

\( K_{eq} \) — Equilibrium constant (dimensionless)
\( [Products] \) — Concentration of products at equilibrium (M)
\( [Reactants] \) — Concentration of reactants at equilibrium (M)

Explanation: For the general reaction aA + bB ⇌ cC + dD, the complete formula is K_eq = [C]^c[D]^d / [A]^a[B]^b.

3. Importance of Keq Calculation

Details: The equilibrium constant helps predict the direction of a reaction, determine reaction yields, and understand how changes in conditions affect chemical equilibrium. It's fundamental in chemical engineering, pharmaceutical development, and environmental chemistry.

4. Using the Calculator

Tips: Enter concentrations in molarity (M). Products concentration must be ≥0, reactants concentration must be >0. For reactions with multiple species, use the product of concentrations raised to their stoichiometric coefficients.

5. Frequently Asked Questions (FAQ)

Q1: What does a large Keq value indicate?
A: A large Keq (>1) indicates the reaction favors product formation at equilibrium, meaning products are more stable than reactants.

Q2: What does a small Keq value indicate?
A: A small Keq (<1) indicates the reaction favors reactant formation at equilibrium, meaning reactants are more stable than products.

Q3: Is Keq affected by temperature?
A: Yes, Keq is temperature-dependent. For exothermic reactions, Keq decreases with increasing temperature; for endothermic reactions, Keq increases with temperature.

Q4: What are the units of Keq?
A: Keq is dimensionless when using activities. When using concentrations, it may have units depending on the reaction stoichiometry, but it's often treated as dimensionless.

Q5: How is Keq related to Gibbs free energy?
A: ΔG° = -RT ln K, where ΔG° is the standard Gibbs free energy change, R is the gas constant, and T is temperature in Kelvin.