Difference Between Arrhenius and Eyring Equation

Thekey difference在Arrhenius和Eyring方程之间Arrhenius equation is an empirical equation whereas Eyring equation is based on the statistical mechanical justification.

Arrhenius equation and Eyring equation are two important equations in physical chemistry. When we are assuming a constantenthalpyof activation and constantentropy激活，眼环方程与经验的Arrhenius方程相似。

CONTENTS

1.Overview and Key Difference
2.What is Arrhenius Equation
3.什么是眼睛方程式
4.Side by Side Comparison – Arrhenius vs Eyring Equation in Tabular Form
5.概括

What is Arrhenius Equation?

Arrhenius equation is a chemical formula that involves the temperature dependence of反应速率. This equation was proposed and developed by the scientist Svante Arrhenius in 1889. The Arrhenius equation has many applications in determining the rate of chemical reactions and in the calculation of the energy of activation. In this context, the Arrhenius equation provides a physical justification and interpretation for the formula. Therefore, we can identify it as an empirical relationship. The Arrhenius equation is expressed as follows:

K = Ae^(Ea/RT)

Where k is the rate constant for the reaction mixture, T is the absolute temperature of the system in Kelvins, A is the pre-exponential factor for the chemical reaction, Ea is the activation energy for the reaction and R is the universal gas constant. In this equation, when considering the units of the pre-exponential factor, A, it is identical to the units of the rate constant that will depend on the order of the reaction. E.g. if the reaction is first order, then the units of A is per second (s^-1). In other words, in this reaction, A is the number of collisions per second that occurs in the proper orientation. Moreover, this relationship describes that either increasing the temperature or decreasing the activation energy will result in the increasing of the rate of reaction.

What Eyring Equation?

Eyring方程是一个方程式，描述了反应混合物温度的化学反应速率的变化。该方程是由亨利·艾林（Henry Eyring）于1935年与另外两名科学家一起开发的。当考虑恒定激活和恒定激活熵时，Eyring方程与Arrhenius方程相似。眼环方程的一般公式如下：

在这里ΔG‡ is the Gibbs energy of activation, κ is the transmission coefficient, kB is Boltzmann’s constant, and h is Planck’s constant.

What is the Difference Between Arrhenius and Eyring Equation?

Arrhenius and Eyring equation are important equations in physical chemistry. The key difference between Arrhenius and Eyring equation is that Arrhenius equation is an empirical equation whereas Eyring equation is based on the statistical mechanical justification. Moreover, Arrhenius equation is used to model the temperature variation of diffusion coefficients, the population of crystal vacancies, creep rates, and many other thermally-induced processes, while Eyring equation is useful in the transition state theory and there, it is known as activated-complex theory.

Below infographic tabulates the differences between Arrhenius and Eyring equation for side-by-side comparison.

概括– Arrhenius vs Eyring Equation

Arrhenius and Eyring equation are important equations in physical chemistry. The key difference between Arrhenius and Eyring equation is that Arrhenius equation is an empirical equation whereas Eyring equation is based on the statistical mechanical justification. Arrhenius equation is used to model the temperature variation of diffusion coefficients, the population of crystal vacancies, creep rates, and many other thermally-induced processes. Eyring equation, on the other hand, is useful in the transition state theory, and there, it is known as activated-complex theory.

Reference:

1.“ 6.2.3.1：arrhenius方程。”化学库，库，2020年9月11日，Available here.
2. “Eyring Equation.”Wikipedia, Wikimedia Foundation, 16 Oct. 2020,Available here.

Image Courtesy:

1. “ArrheniusMundim new” By Kleber Carlos Mundim – Own work(CC BY-SA 4.0)viaCommons Wikimedia