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Topic: Average molar mass derivation problem  (Read 3655 times)

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Offline grignardgirl

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Average molar mass derivation problem
« on: June 12, 2008, 12:29:33 AM »
So we were given this problem on a practice exam and our professor will not tell us how to do it at all, meaning that it will be on the exam tomorrow.  So I'm hoping someone can help me!

A protein of molar mass M dimerizes when allowed to stand in solution at room temperature.  A possible mechanism is that the protein is first denatured before it dimerizes.

P  --k1--> P*    (denatured)  slow
2P*  --k2--> P2  fast

Then progress of the reaction can be followed by making viscosity measuerements of the average molar mass <M>.  Derive and expression for <M> in terms of the initial concentration [P]o, the concentration at time t [P], and M.  Write a rate equation consistent with this scheme. 

The answers are:

<M> = 2M[P]o/([P]o + [P])

ln((2M-<M>)/<M>) = -kt



I know it has some stuff to do with fractions and integrations (distributions basically) but beyond  that I have no idea.  Thanks!!

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