Arrhenius Behavior

[Ava Harvey 2B]

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]

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]

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]

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