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Topic: Reaction rate.  (Read 5726 times)

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Offline Tasnim

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Reaction rate.
« on: October 30, 2010, 12:07:51 PM »
Is it possible to predict rate equations for reactions? Please someone quick help. :-\
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Offline Cherriyan

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Re: Reaction rate.
« Reply #1 on: October 30, 2010, 12:15:08 PM »
For this, you need to know the order of the reaction. Practically, you can carry out the reaction and study the concentration of the reactants with time.
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Offline rabolisk

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Re: Reaction rate.
« Reply #2 on: October 30, 2010, 12:19:12 PM »
It is possible to predict from the mechanism of the reactions. But in practice, mechanisms are deduced from the data.
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Offline Tasnim

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Re: Reaction rate.
« Reply #3 on: October 30, 2010, 12:21:12 PM »
What I meant was, is it possible to predict exactly of what order a reaction will be?
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Offline opti384

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Re: Reaction rate.
« Reply #4 on: October 30, 2010, 12:24:06 PM »
In order to determine that, data from experiments are required because the reaction could go in several steps.
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Offline Tasnim

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Re: Reaction rate.
« Reply #5 on: October 30, 2010, 12:27:33 PM »
Is it possible to predict the steps without using raw data? : ???
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Offline opti384

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Re: Reaction rate.
« Reply #6 on: October 30, 2010, 12:53:12 PM »
If the reaction is just a single step reaction, yes.
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Offline Tasnim

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Re: Reaction rate.
« Reply #7 on: October 31, 2010, 01:55:27 AM »
Does the order of a reaction depend upon the steps involved? What about the rate-determining step? Does it not determine the order? Can the steps of a reaction be predicted, for a many-steps reaction?
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Offline opti384

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Re: Reaction rate.
« Reply #8 on: October 31, 2010, 02:16:59 AM »
Yes, the order of the rate-determining step could be the order of the whole reaction.

Quote from: Tasnim on October 31, 2010, 01:55:27 AM
Can the steps of a reaction be predicted, for a many-steps reaction?

Do you mean by saying that by looking at 2NO + O2  :rarrow: 2NO2

it's possible to predict the whole mechanism

NO+NO  :rarrow: N2O2
N2O2 + O2  :rarrow: 2NO2 ?
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Offline Tasnim

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Re: Reaction rate.
« Reply #9 on: October 31, 2010, 02:33:28 AM »
So if there is one rate-determining step it is of first order, something like that.
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Offline opti384

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Re: Reaction rate.
« Reply #10 on: October 31, 2010, 02:44:48 AM »
If the rate-determining step is a first order reaction, the overall reaction order will be the same.
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Offline Tasnim

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Re: Reaction rate.
« Reply #11 on: October 31, 2010, 02:50:20 AM »
I guess I get it now, but is not possible anyhow to predict reactions form molecular structure of reactants.
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Offline Tasnim

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Re: Reaction rate.
« Reply #12 on: November 05, 2010, 08:49:05 AM »
help anyone? :-\
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