[gradu8in2003]

Two questions...
First: I was asked to determine the approximate energy difference between an anti and gauche configuration and came out with 0.9288 kcal.

I need to figure out at what percentage does the anti conformer exist in equilibrium with the gauche? My textbook (Fox & Whitesell) has a small table with energy vs percentage with 0.65 kcal = 75% and 1.3 kcal = 90%, so obviously my answer is between the two, but is there a way to calculate this precisely?


Second: We were given the graph of the Arrhenius equation with the rate as a function of temperature for an endothermic reaction and asked to graph one for exothermic.
Our endothermic began at 0K and 0rate and increased exponentially to a leveled off value equal to A at a high temp (just trying to give y'all an idea of how it looks).
Therefore, my graph for exothermic is amost exactly backwards, where it increases exponentially and indefinitely at the A value... but i'm not sure this is right.

As part of the explanation for this problem, I am supposed to determine why an exothermic reaction is not very likely for a unimolecular/one-step reaction.

Thanks for any help y'all can give!

[sjb]

Two questions...
First: I was asked to determine the approximate energy difference between an anti and gauche configuration and came out with 0.9288 kcal.

I need to figure out at what percentage does the anti conformer exist in equilibrium with the gauche? My textbook (Fox & Whitesell) has a small table with energy vs percentage with 0.65 kcal = 75% and 1.3 kcal = 90%, so obviously my answer is between the two, but is there a way to calculate this precisely?

n_{isomer 1}/n_{isomer 2} = e^{-(difference in energy)/RT} (where energy is in joules), I seem to recall.


S