Arrhenius Behavior

Arrhenius Equation:

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Ava Harvey 2B
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Joined: Fri Sep 29, 2017 7:04 am

Arrhenius Behavior

Postby Ava Harvey 2B » Sun Mar 04, 2018 4:31 pm

What exactly does it mean to exhibit Arrhenius Behavior, and why is it helpful to know if a certain reaction exhibits it? Thanks so much!

Vasiliki G Dis1C
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

Re: Arrhenius Behavior

Postby Vasiliki G Dis1C » Sun Mar 04, 2018 5:39 pm

Hey Ava!!!

Exhibiting Arrhenius behavior means that the plot of lnk against 1/T for a reaction gives a straight line (lnk on the y, 1/T on the x). Since the slope of an Arrhenius plot is proportional to the activation energy, the higher the activation energy, the stronger the temperature dependent of the rate constant. When a reaction does not have a steep Arrhenius plot, it has a low activation energy and its rate increases only a little with temperature. When a reaction has a steep Arrhenius plot, it has a high activation energy and its rate depends strongly on the temperature. The Arrhenius behavior indicates how much the rate of the reaction is influenced by temperature. Hope this helps!

Mike Vinci 2B
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Joined: Fri Sep 29, 2017 7:03 am
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Re: Arrhenius Behavior

Postby Mike Vinci 2B » Sun Mar 04, 2018 5:47 pm

Hi Ava,
When I found information on Arrhenius behavior in 15.11. The book describes it as "reactants that give a straight line when ln k is plotted against 1/T. I'm not exactly sure what questions Professor Lavelle will ask, however the Arrhenius equation is ln k= ln A -Ea/RT or k=Ae^-Ea/RT. Ea, the activation energy, and A, the pre-exponential factor, are found experimentally, so they will likely be given. With this equation, we can derive an additional equation, ln k2/k1 = Ea/R(1/T1 - 1/T2), which we can use to predict the value of a rate constant at one temperature from its value at another temperature.

Mike

Silvino Jimenez 1A
Posts: 52
Joined: Fri Sep 29, 2017 7:04 am

Re: Arrhenius Behavior

Postby Silvino Jimenez 1A » Tue Mar 06, 2018 3:01 am

Useful equation to predict the value of a rate constant at one temperature from its value at another temperature!


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