Abstract
The van’t Hoff equation, which is used to calculate the effect of temperature on equilibrium constants, was derived from the Gibbs – Helmholtz equation that relates the molar Gibbs free energy to the molar enthalpy of a chemical reaction. However, the Gibbs – Helmholtz equation was developed for systems that do not consider contributions of Gibbs free energy from chemical species. Consequently, the van’t Hoff equation and the Arrhenius equation derived from it are technically incomplete.
By employing Hess’s law and the appropriate Gibbs free energy equation for chemical reaction systems, this investigation develops theoretical equations to calculate the effects of temperature and pressure on chemical reaction equilibrium and kinetics, respectively, without relying on the Gibbs – Helmholtz equation. It also demonstrates that, for rate-limiting reactions, the kinetic constant equals the equilibrium constant. These findings not only improve equilibrium and kinetic calculations, but also open new avenues for investigating chemical reaction mechanisms.
Recommended Citation
J. Wang, "Reevaluating the van’t Hoff and Arrhenius Equations: How Temperature and Pressure Affect Chemical Reaction Thermodynamics, Equilibrium, and Kinetics,", Jan 2025.
Department(s)
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Equilibrium, Kinetics, Temperature, Pressure, van’t Hoff equation, Arrhenius equation
Document Type
Article - Preprint
Document Version
Preprint
File Type
text
Language(s)
English
Rights
© 2025 Jianmin Wang, All rights reserved
Publication Date
2025
