Enter the temperature, ΔH, and ΔS into the calculator to determine the rate constant using the Eyring equation.

Eyring Equation Formula

The Eyring equation is used to calculate the rate constant (k) of a chemical reaction at a given temperature (T). The formula is as follows:

k = e^{((ΔS/R) - (ΔH/(R*T)))}

Variables:

  • k is the rate constant (s-1)
  • ΔS is the entropy change (J/mol·K)
  • ΔH is the enthalpy change (J/mol)
  • R is the universal gas constant (8.314 J/(mol·K))
  • T is the temperature (K)

To calculate the rate constant using the Eyring equation, you need to know the temperature, the enthalpy change, and the entropy change of the reaction. The rate constant is a measure of the speed of the reaction and is influenced by these thermodynamic properties.

What is the Eyring Equation?

The Eyring equation, also known as the Eyring-Polanyi equation, is a theoretical model that describes the rate at which chemical reactions occur. It is based on transition state theory and provides a relationship between the rate constant of a reaction and the temperature, as well as the enthalpy and entropy of activation. The equation is particularly useful in the field of chemical kinetics and is widely used to predict reaction rates and understand reaction mechanisms.

How to Calculate Rate Constant Using the Eyring Equation?

The following steps outline how to calculate the rate constant using the Eyring equation.

  1. First, determine the temperature (T) at which the reaction occurs in Kelvin (K).
  2. Next, determine the enthalpy change (ΔH) of the reaction in joules per mole (J/mol).
  3. Then, determine the entropy change (ΔS) of the reaction in joules per mole per Kelvin (J/mol·K).
  4. Use the Eyring equation: k = e^((ΔS/R) – (ΔH/(R*T))) to calculate the rate constant (k).
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Temperature (T) = 298 K

Enthalpy change (ΔH) = 40,000 J/mol

Entropy change (ΔS) = 100 J/mol·K