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Standard Gibbs Energy

ΔG° = ΔH° - TΔS° = -RT ln K
Quick Reference
Formula / NotationΔG° = ΔH° - TΔS° = -RT ln K
Also Known AsStandard Gibbs free energy, ΔG°, standard free energy change

What is Standard Gibbs Energy?

The Gibbs free energy change for a reaction under standard conditions (298 K, 1 bar, 1 M). Calculated from standard enthalpy and entropy: ΔG° = ΔH° - TΔS°. Related to the equilibrium constant: ΔG° = -RTlnK. Negative ΔG° indicates the reaction favors products at equilibrium.

Formula & Notation

ΔG° = ΔH° - TΔS° = -RT ln K

Other Names / Synonyms: Standard Gibbs free energy, ΔG°, standard free energy change

Properties & Characteristics

Standard Gibbs energy change (ΔG°) is the change in Gibbs free energy under standard conditions (25°C, 1 bar, unit activities). It is related to the standard equilibrium constant K by ΔG° = -RT ln K. A negative ΔG° indicates spontaneous reaction under standard conditions. Standard Gibbs energy is calculated from standard enthalpies and entropies of formation.

Uses & Applications

Standard Gibbs energy is used to calculate equilibrium constants and predict reaction feasibility. It is tabulated for compounds and used in thermodynamic databases for process design. ΔG° values guide the synthesis of high-energy compounds and assessment of reaction energetics.

Safety Information

Large negative ΔG° values indicate highly exergonic reactions, which may be rapid and hazardous. This thermodynamic data is used in hazard assessments of reactive chemical processes.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Standard Gibbs Energy
Formula ΔG° = ΔH° - TΔS° = -RT ln K
Synonyms Standard Gibbs free energy, ΔG°, standard free energy change

Frequently Asked Questions

The Gibbs free energy change for a reaction under standard conditions (298 K, 1 bar, 1 M). Calculated from standard enthalpy and entropy: ΔG° = ΔH° - TΔS°. Related to the equilibrium constant: ΔG° = -RTlnK. Negative ΔG° indicates the reaction favors products at equilibrium.

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