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Topic: Another question writtin wrong?  (Read 6509 times)

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Offline rcole23

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Another question writtin wrong?
« on: August 24, 2009, 02:24:50 PM »
Question 7) Consider the reaction for synthesis of ester, ethyl acetate

CH3COOH(l) + CH3CH2OH(l)   CH3COOCH2CH3(l) + H2O(l)

Various samples were analyzed.  The concentrations are given in the table below.  Describe whether each sample is at equilibrium.  If it is not at equilibrium predict the direction in which the reaction will proceed to establish equilibrium. (8 marks)

Sample   CH3COOH(l)   CH3CH2OH(l   CH3COOCH2CH3(l)   H2O(l)
a)   0.10                0.10                   0.10               0.10
b)   0.084                     0.13                         0.16   0.28
c)   0.14                  0.21                       0.33   0.20
d)   0.063                    0.11                       0.15   0.17

Impossible to answer because a value of Kc is not given in this question?  If Kc is not listed then I cannot compare it to Qc.  As I cannot compare Kc to Qc no determination of Qc being greater than, less than or equal to Kc is able to be formed.  Therefore this question cannot be answered and I believe it is written wrongly.

Anyone able to backup my thoughts?

Offline Fridushka

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Re: Another question writtin wrong?
« Reply #1 on: August 24, 2009, 05:01:31 PM »
It's given that the samples are analyzed..so those number of moles should be the final right or i understood wrong?!..moreover if i'm right then u dont have the initial value in order to know the Qc...

Offline rcole23

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Re: Another question writtin wrong?
« Reply #2 on: August 24, 2009, 06:29:22 PM »
It's given that the samples are analyzed..so those number of moles should be the final right or i understood wrong?!..moreover if i'm right then u dont have the initial value in order to know the Qc...

Well since it is analyzed then these must be the final values not the intermediate values in which I could use to determine direction of equilibrium so yes, you may have a point there.

When I add up the quantities of substances the total is different in every line...  I was thinking that the start would be 2 moles because of no interger infront of the chemical formula but nothing adds up to 2. 


No having Kc or a value to compare it to, or a value to calcualte anything from, or an initial value plus your statements makes me belive that this question is wrong in the book.  I can calucalte Kc, but then I cannot compare it to anything..

Offline Harlz420

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Re: Another question writtin wrong?
« Reply #3 on: August 15, 2011, 04:00:42 PM »
Can I *Ignore me, I am impatient* this for opinions? I have the same questions same dilemma, and this was never really answered here.. can this be solved?

Online Borek

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Re: Another question writtin wrong?
« Reply #4 on: August 16, 2011, 03:11:24 AM »
I don't see how this can be solved without additional information.

But then, I am known to be occasionally wrong.
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Offline Harlz420

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Re: Another question writtin wrong?
« Reply #5 on: August 16, 2011, 02:13:08 PM »
 found this question in the textbook online, they left out the Kc=2.2

:facepalm:

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