Gibbs Free Energy Formula:
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Definition: This calculator computes the Gibbs free energy change for a chemical reaction based on temperature and the equilibrium constant with respect to partial pressures.
Purpose: It helps chemists and chemical engineers determine the spontaneity and thermodynamic favorability of reactions under specific conditions.
The calculator uses the formula:
Where:
Explanation: The formula relates the thermodynamic equilibrium constant to the standard Gibbs free energy change of a reaction.
Details: Gibbs free energy determines whether a reaction will occur spontaneously. Negative values indicate spontaneous reactions, while positive values indicate non-spontaneous reactions.
Tips: Enter the temperature in Kelvin and the equilibrium constant for partial pressure. Both values must be > 0.
Q1: What does a negative Gibbs free energy value mean?
A: A negative value indicates the reaction is thermodynamically favorable and will proceed spontaneously under the given conditions.
Q2: Why do we use natural logarithm in the formula?
A: The natural logarithm relates the equilibrium constant to the exponential term in the Boltzmann factor of statistical mechanics.
Q3: What's the significance of the 2.303 factor?
A: This factor converts from natural logarithm to base-10 logarithm (2.303 ≈ ln(10)), making the formula compatible with common log-based equilibrium constants.
Q4: How does temperature affect Gibbs free energy?
A: Higher temperatures typically increase the magnitude of the Gibbs free energy change, making the temperature-dependence of reactions more pronounced.
Q5: What units should be used for Kp?
A: The equilibrium constant should be dimensionless (unitless), but the calculator accepts mol/m³ for practical calculations.