1. What is the Equilibrium Constant?

The equilibrium constant (K) quantifies the position of chemical equilibrium in a reversible reaction. It relates the Gibbs free energy change (ΔG) to the equilibrium state through thermodynamic principles.

2. How Does the Calculator Work?

The calculator uses the fundamental thermodynamic equation:

Where:

• \( K \) — Equilibrium constant (dimensionless)
• \( \Delta G \) — Gibbs free energy change (J/mol)
• \( R \) — Universal gas constant (8.314 J/mol·K)
• \( T \) — Absolute temperature (K)
• \( e \) — Euler's number (base of natural logarithm)

Explanation: This equation connects thermodynamics with chemical equilibrium, showing how the spontaneity of a reaction (ΔG) determines the equilibrium position.

3. Importance of Equilibrium Constant

Details: The equilibrium constant is crucial for predicting reaction direction, calculating yields, understanding chemical systems, and designing industrial processes. It provides quantitative insight into reaction feasibility.

4. Using the Calculator

Tips: Enter Gibbs free energy in J/mol and temperature in Kelvin. Ensure temperature is positive and in absolute scale. The gas constant is fixed at 8.314 J/mol·K.

5. Frequently Asked Questions (FAQ)

Q1: What does a large K value indicate?
A: K > 1 indicates products are favored at equilibrium, while K < 1 indicates reactants are favored. Very large K values suggest the reaction proceeds nearly to completion.

Q2: How does temperature affect K?
A: For exothermic reactions (ΔG < 0), K decreases with increasing temperature. For endothermic reactions (ΔG > 0), K increases with temperature.

Q3: What are typical units for ΔG?
A: Gibbs free energy is typically expressed in J/mol or kJ/mol. This calculator uses J/mol for consistency with the gas constant.

Q4: Can this be used for biological systems?
A: Yes, but ensure temperature is in Kelvin and concentrations are appropriate for the system being studied.

Q5: What is the relationship between K and ΔG?
A: When ΔG < 0, K > 1 (spontaneous forward reaction). When ΔG > 0, K < 1 (non-spontaneous forward reaction). When ΔG = 0, K = 1 (system at equilibrium).