Arrhenius Equation and pseudo isotherms

In summary, the conversation discusses the possibility of extracting the Arrhenius parameters from an experiment where a reaction is run at different microwave powers and temperatures. While the professor believes it is possible, the speaker is unsure and is seeking further information. The process may involve knowing the reaction rate at different temperatures and the adiabatic conditions of the reaction system.
  • #1
opaka
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Hey, I'm doing an experiment where I run a reaction at three different microwave powers to determine if there is any effect beyond the standard temperature ramp rates. If I know how long it takes the reaction to go from 260 C to 280 C in each of these cases, is there any possible way to extract the Arrhenius parameters? I don't think there is, but my professor is certain he's seen it done, he just can't remember how.
 
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  • #2
opaka said:
Hey, I'm doing an experiment where I run a reaction at three different microwave powers to determine if there is any effect beyond the standard temperature ramp rates. If I know how long it takes the reaction to go from 260 C to 280 C in each of these cases, is there any possible way to extract the Arrhenius parameters? I don't think there is, but my professor is certain he's seen it done, he just can't remember how.
Arrhenius equation involves reaction rate, activation energy, temperature, and frequency factor. When you say Arrhenius parameter, I am assuming you want to know the activation energy and the frequency factor. You need to know the reaction rate at different temperatures.

If the entire reaction system is adiabatic, then if you know how much heat is being released (per mole of reaction), how much actually reacted (or initial reaction rate), and you know the molar heat capacity of the system (the part where you are using thermometer for), then I assume it is theoretically possible.
 

FAQ: Arrhenius Equation and pseudo isotherms

What is the Arrhenius Equation and how is it used?

The Arrhenius Equation is a mathematical expression that relates the rate of a chemical reaction to its temperature. It is used to calculate the activation energy of a reaction and predict how changing the temperature will affect the reaction rate.

What are the assumptions made in the Arrhenius Equation?

The Arrhenius Equation assumes that the reaction follows a simple two-step process, with an initial reversible step followed by an irreversible step. It also assumes that the activation energy for the reaction is constant over the temperature range being studied.

What is a pseudo isotherm and how does it differ from a regular isotherm?

A pseudo isotherm is a type of adsorption isotherm that is used to describe the behavior of adsorbates on heterogeneous surfaces, where the adsorption energy varies depending on the surface site. Unlike a regular isotherm, which assumes a uniform adsorption energy, a pseudo isotherm takes into account the heterogeneity of the surface.

What factors can affect the accuracy of pseudo isotherm models?

The accuracy of pseudo isotherm models can be affected by factors such as the heterogeneity of the surface, the range of temperatures studied, and the assumptions made in the model. Other factors that can impact the accuracy include the type of adsorbate and the presence of other molecules in the system.

How is the Arrhenius Equation used to determine the adsorption parameters in pseudo isotherm models?

The Arrhenius Equation can be used to calculate the activation energy and pre-exponential factor for the adsorption process in pseudo isotherm models. These parameters can then be used to fit the experimental data and determine the best-fit model for the adsorption system.

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