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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: sweetdaisy186 on July 22, 2005, 09:07:16 PM

Title: Provide mechanism involving...
Post by: sweetdaisy186 on July 22, 2005, 09:07:16 PM

Provide a mechanism that involves a catalyst, Cat, and an intermediate, I, that aggress with the rate law, rate = k[cat][A] for the net reaction A + 2B-> C + D.

I don't understand the whole mechanism term. What does that mean? My teacher gave me a hint and said that I'm not supposed to give a graph, but apply a Hess's Law type concept. I am still confused. Could someone please give me an example? Thanks!

Title: Re:Provide mechanism involving...
Post by: Donaldson Tan on July 23, 2005, 12:02:37 AM

reaction mechanism refers to how a chemical reaction occurs step by step. the overall reaction gives us the stoichiometric balance of all the reactants and products. it does not account for intermediates. in writing out the reaction mechanism, the intermediates are accounted for. the intermediate present may be consumed in another reaction step as soon it is formed.

Title: Re:Provide mechanism involving...
Post by: sweetdaisy186 on July 23, 2005, 09:05:15 PM

Hmmm, that makes a lot of sense. Thanks!

Would this be correct then?

A + Cat + B --> I + D
I + B --> C + Cat

All of this adds up to A + 2B --> C + D with the rate=K[cat][A]

Thanks!

Title: Re:Provide mechanism involving...
Post by: Donaldson Tan on July 24, 2005, 06:34:11 PM

it's correct. you must also label the first step as the slow step, aka rate-determining step.

 :thmbup:

Title: Re:Provide mechanism involving...
Post by: sweetdaisy186 on July 24, 2005, 10:50:18 PM

OMG! yea!!!! I know what I am doing!!! That makes my happy!!! Thanks for your *delete me*!!  ;D