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Topic: Reasonable rate of reaction  (Read 3563 times)

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Offline Inventor22

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Reasonable rate of reaction
« on: November 03, 2010, 11:43:49 PM »
Hi everyone, I just have one small question.

I recently wrote a test in chemistry.
one of the questions was to determine the rate law for some reaction between two aqueous chemicals.
determining half of the rate law, I obtained:  r = k[A]^2[ B].
substituting a trial into this equation (i.e. r, [A] and [ B] values), I solved for K.
The problem was not calculating K, but it was a discrepancy in the trial(s) themselves.

In first trial was the following information was given:

  [A]             [ B]            rate
0.1 mol/L   0.1 mol/L    12 mol/L/s

I am just wondering if it is actually possible for two chemicals who's concentration are both .o1 moles/liter (assuming a molar ratio of 1:1 for the reactants i.e. A+B -> products) to react at a rate of  12 mols/liter/second?

Offline sjb

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Re: Reasonable rate of reaction
« Reply #1 on: November 04, 2010, 04:14:12 PM »
Hi everyone, I just have one small question.

I recently wrote a test in chemistry.
one of the questions was to determine the rate law for some reaction between two aqueous chemicals.
determining half of the rate law, I obtained:  r = k[A]^2[ B].
substituting a trial into this equation (i.e. r, [A] and [ B] values), I solved for K.
The problem was not calculating K, but it was a discrepancy in the trial(s) themselves.

In first trial was the following information was given:

  [A]             [ B]            rate
0.1 mol/L   0.1 mol/L    12 mol/L/s

I am just wondering if it is actually possible for two chemicals who's concentration are both .o1 moles/liter (assuming a molar ratio of 1:1 for the reactants i.e. A+B -> products) to react at a rate of  12 mols/liter/second?

The rate constant is independent (to a large extent) of the concentration of the reactants. However, saying that if the concentration of the reactants is only 0.1M I wonder if you can accurately determine such a large rate?

Offline rackye

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Re: Reasonable rate of reaction
« Reply #2 on: November 05, 2010, 07:40:53 PM »
I don't think that's possible because if you use the stecheometric relationship between reactants they all react completely and you will get the addition of the amounts by the law of the mass conservation

Offline Borek

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Re: Reasonable rate of reaction
« Reply #3 on: November 06, 2010, 05:21:31 AM »
I don't think that's possible because if you use the stecheometric relationship between reactants they all react completely and you will get the addition of the amounts by the law of the mass conservation

Not sure what you are aiming at, but speed of the reaction is not limited by the amount of reactants, just like speed of the object is not limited by the distance it has to cover.
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Offline rackye

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Re: Reasonable rate of reaction
« Reply #4 on: November 06, 2010, 12:03:31 PM »
I don't think that's possible because if you use the stecheometric relationship between reactants they all react completely and you will get the addition of the amounts by the law of the mass conservation

Not sure what you are aiming at, but speed of the reaction is not limited by the amount of reactants, just like speed of the object is not limited by the distance it has to cover.

You are totally right i got confuse

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