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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Bkkkk on May 18, 2005, 05:48:39 PM

Title: Arrhenius - Decomp of H2O2
Post by: Bkkkk on May 18, 2005, 05:48:39 PM
Hey guys, im new to this place but I thought id post this up....

As part of a simulated practical I need to use the Arrhenius equation to find the activation energy of this reaction in different temperatures.

Now the data I collected is the volume versus the time taken up to 20 mins, for each temperature, I did 5 temps as a friend of mine did 5 more.

Now I know that the Arrhenius Equation can be Natural Log and will look like this:

ln(k) = -E/R x 1/T + ln(A)

But im stuck after I plotted the graph of different temps.
I know that the reaction is first order however I have no idea what to do, I think i might be able to draw a graph of 1/T against ln(k) however I dont have ln(k) or k for that matter.
Title: Re:Arrhenius - Decomp of H2O2
Post by: Donaldson Tan on May 18, 2005, 07:07:52 PM
i hope you have data for the reaction rate.

assuming H2O2 decomposition is first order,
rate = k[H2O2]
k = rate/[H2O2]

this is how you extract the value of k from your experiments.

i assume the volume changes is due to accummulation of oxygen. plot a graph of moles of oxygen against time. you may extract the reaction rate by finding the instantaneous gradient of the graph at that particular point, with its corresponding volume of O2 formed. do a mole balance to find what is the corresponding [H2O2] in the reaction mixture.