pseudo first order  [ENDORSED]


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Ashley McClearnen 1B
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Joined: Fri Sep 28, 2018 12:26 am

pseudo first order

Postby Ashley McClearnen 1B » Wed Mar 13, 2019 5:19 pm

In pseudo 1st order rate laws, why are the reactants in large excess left out?

Chem_Mod
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Re: pseudo first order

Postby Chem_Mod » Wed Mar 13, 2019 6:39 pm

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.

Marina Gollas 1A
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Re: pseudo first order

Postby Marina Gollas 1A » Thu Mar 14, 2019 5:39 am

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.

Megan_Ervin_1F
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Re: pseudo first order  [ENDORSED]

Postby Megan_Ervin_1F » Sat Mar 16, 2019 4:20 pm

You make the other concentrations so big that they are essentially viewed as constant so the rate law becomes "fake" first order

Madison Hurst
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Re: pseudo first order

Postby Madison Hurst » Sat Mar 16, 2019 10:49 pm

So is it technically a second order reaction, but because one of the concentrations is so big its basically constant?

paytonm1H
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Re: pseudo first order

Postby paytonm1H » Sat Mar 16, 2019 10:51 pm

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


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