Equilibrium Constant Formula:
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Definition: The equilibrium constant (Kp) expresses the ratio of product partial pressures to reactant partial pressures at equilibrium, each raised to the power of their stoichiometric coefficients.
Purpose: It quantifies the position of equilibrium for gas-phase reactions and helps predict reaction behavior under different conditions.
The calculator uses the formula:
Where:
Explanation: The formula relates the thermodynamic quantity Gibbs free energy to the equilibrium constant through the exponential function.
Details: Knowing Kp helps predict reaction direction, extent of reaction, and the effect of changing conditions on chemical equilibrium.
Tips: Enter the Gibbs free energy change (ΔG) in Joules and temperature in Kelvin. Temperature must be > 0K.
Q1: What does a large Kp value indicate?
A: A large Kp (>1) indicates products are favored at equilibrium, while a small Kp (<1) indicates reactants are favored.
Q2: How does temperature affect Kp?
A: For endothermic reactions, Kp increases with temperature. For exothermic reactions, Kp decreases with temperature.
Q3: What units should be used for Gibbs free energy?
A: The calculator expects Gibbs free energy in Joules (J). If you have kJ, multiply by 1000 before entering.
Q4: Why is the natural logarithm base used?
A: The relationship between ΔG and K comes from thermodynamic principles where the natural logarithm form appears naturally.
Q5: Can this be used for solutions?
A: No, this calculates Kp for gas-phase reactions. For solutions, use Kc which uses concentrations.