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pseudo first order

Posted: Wed Mar 13, 2019 5:19 pm
by Ashley McClearnen 1B
In pseudo 1st order rate laws, why are the reactants in large excess left out?

Re: pseudo first order

Posted: Wed Mar 13, 2019 6:39 pm
by Chem_Mod
If one of the concentration is extremely large, then its concentration essentially remains unchanged. Thus the concentration for this item could be considered constant and be incorporated into the rate constant. As a result, it will look as if it were only a first order reaction.

Re: pseudo first order

Posted: Thu Mar 14, 2019 5:39 am
by Marina Gollas 1A
What is a pseudo first order rate law again? My TA tried to explain it, but I still didn't really understand it. Sorry if this is a dumb question.

Re: pseudo first order  [ENDORSED]

Posted: Sat Mar 16, 2019 4:20 pm
by Megan_Ervin_1F
You make the other concentrations so big that they are essentially viewed as constant so the rate law becomes "fake" first order

Re: pseudo first order

Posted: Sat Mar 16, 2019 10:49 pm
by Madison Hurst
So is it technically a second order reaction, but because one of the concentrations is so big its basically constant?

Re: pseudo first order

Posted: Sat Mar 16, 2019 10:51 pm
by paytonm1H
Madison Hurst wrote:So is it technically a second order reaction, but because one of the concentrations is so big its basically constant?


it is pseudo first order with respect to the reactant you are focusing on, I think