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Equilibrium Constant Formula:
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The equilibrium constant (K) quantifies the ratio of products to reactants at equilibrium for a chemical reaction. It is calculated from the standard Gibbs free energy change (ΔG°) using thermodynamic principles.
The calculator uses the fundamental thermodynamic relationship:
Where:
Explanation: This equation relates the thermodynamic driving force (ΔG°) to the position of equilibrium. A negative ΔG° indicates a spontaneous reaction with K > 1, while a positive ΔG° indicates K < 1.
Details: The equilibrium constant is fundamental in predicting reaction direction, extent, and composition at equilibrium. It's essential for chemical engineering, biochemistry, and environmental science applications.
Tips: Enter ΔG° in kJ/mol and temperature in Kelvin. Ensure temperature is positive and in absolute scale. The calculator automatically handles unit conversions.
Q1: What does the magnitude of K indicate?
A: K > 1 favors products, K < 1 favors reactants, and K ≈ 1 indicates significant amounts of both.
Q2: Why use Kelvin for temperature?
A: The gas constant R is defined using Kelvin, and thermodynamic equations require absolute temperature.
Q3: What is standard state for ΔG°?
A: Standard state is 1 atm pressure for gases and 1 M concentration for solutions at 298 K, unless specified otherwise.
Q4: Can this be used for any temperature?
A: Yes, but ΔG° values are typically tabulated at 298 K. For other temperatures, temperature-dependent ΔG° is needed.
Q5: How does ΔG° relate to reaction spontaneity?
A: ΔG° < 0 indicates spontaneous reaction under standard conditions, ΔG° > 0 indicates non-spontaneous, and ΔG° = 0 indicates equilibrium.