Equilibrium Constant Calculator

Calculate Kc and Kp from equilibrium concentrations and convert between them.

⚖️ Equilibrium Constant (Kc)

For reaction: aA + bB ⇌ cC + dD

[C] mol/L

[D] mol/L

[A] mol/L

[B] mol/L

⚠ Enter valid concentrations/pressures.

Equilibrium Expression

Kc = [C]ᶜ[D]ᵈ / [A]ᵃ[B]ᵇ

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⚖️ Equilibrium Constant

Kc = [C]ᶜ[D]ᵈ / [A]ᵃ[B]ᵇ

Kp = Kc(RT)^Δn Δn = (c+d) − (a+b)

K ≫ 1

Products favored

K ≈ 1

Mixed equilibrium

K ≪ 1

Reactants favored

📖 Example

✅ N₂ + 3H₂ ⇌ 2NH₃

At equilibrium: [N₂]=0.5, [H₂]=0.3, [NH₃]=2.0 mol/L

Kc = [NH₃]² / ([N₂][H₂]³)

Kc = (2.0)² / (0.5 × 0.3³) = 4 / 0.0135 = 296

K ≫ 1 → Products strongly favored

❓ FAQ

What does K tell us?

K tells us the ratio of products to reactants at equilibrium. K > 1 means products dominate; K < 1 means reactants dominate.

Do solids and liquids appear in K?

No. Only gases and dissolved species (aqueous) appear in the equilibrium expression. Pure solids and liquids have fixed activity = 1.

🔗 Related

Comprehensive Guide

Understanding Equilibrium Constant: A Complete Guide

The Equilibrium Constant Calculator is an essential analytical tool for chemistry students, educators, and laboratory professionals. Accurate Equilibrium Constant calculations form the backbone of both theoretical studies and physical experiments. Mastering the concepts behind Equilibrium Constant is crucial for understanding advanced chemical reactions and laboratory procedures.

Why is Equilibrium Constant Important?

In analytical chemistry, precision is everything. Having a reliable way to compute Equilibrium Constant saves time, prevents wasted materials, and ensures scientific accuracy.

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Speed

Instant

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Accuracy

100%

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Level

All Levels

Always verify your input units before calculating. Mismatched units (e.g., using mL instead of L) are the most common source of error when determining Equilibrium Constant!

Common Applications

Academic Study: Verifying manual homework calculations.
Laboratory Practice: Standardizing lab reagent preparations.
Data Validation: Cross-checking experimental data analysis.

Relying solely on the calculator without understanding the underlying formula. Always review the step-by-step breakdown to internalize the mechanics.