### Arrhenius Equation

Posted:

**Thu Mar 08, 2018 12:04 am**When do you use the Arrhenius Equation?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=151&t=29213

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Posted: **Thu Mar 08, 2018 12:04 am**

When do you use the Arrhenius Equation?

Posted: **Thu Mar 08, 2018 1:14 am**

You can use the Arrhenius equation to show the effect a change of temperature has on the rate constant (and thus the reaction as well). Hope this helps!

Posted: **Fri Mar 09, 2018 12:40 pm**

To be add on for when we use the Arrhenius Equation, it is clear we need to use it if we are working with the Boltzmann distribution e^-Ea/R, which gives the fractions of collisions wth energy,Ea, or greater temp at T. In this case, A would be the frequency factor or pre-exponential factor (includes #collisions with correct orientation).

Arrhenius Equation with Graphs:

If you are working with a graph, you use Arrhenius Theory by looking at the plot of lnk vs. 1/T. then the plot will be linear with the slope m=-Ea/RT.

Arrhenius Equation with Graphs:

If you are working with a graph, you use Arrhenius Theory by looking at the plot of lnk vs. 1/T. then the plot will be linear with the slope m=-Ea/RT.

Posted: **Fri Mar 09, 2018 5:54 pm**

Whenever you see a kinetics question that involves temperature change, you're most likely gonna use the Arrhenius equation.

Posted: **Fri Mar 09, 2018 8:00 pm**

When using the Arrhenius Equation, are we always going to use it in the form k=... or are we going to have to know how to re-arrange it and solve?

Posted: **Fri Mar 09, 2018 9:22 pm**

Definitely need to know how to re-arrange it and solve for Ea. See HW problems.

Posted: **Sat Mar 10, 2018 12:04 am**

I have heard that when plugging in values for Ea, you want to convert the units to joules, or else your answer will be incorrect. Is this because R is in J/mol*k?

Posted: **Sat Mar 10, 2018 3:50 pm**

how would you find A (frequency factor) in the Arrhenius Equation?