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Topic: Balance this equation and determine theoretical yield?  (Read 5708 times)

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Offline 58Fred

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Balance this equation and determine theoretical yield?
« on: October 29, 2016, 07:26:13 PM »
So I use 0.6 grams of dimedone and 0.2 grams of benzaldehyde.

http://pubs.acs.org/doi/pdf/10.1021/ed400457c
I need to balance the reaction and then determine a theoretical yield.
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Offline AWK

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Re: Balance this equation and determine theoretical yield?
« Reply #1 on: October 29, 2016, 07:42:47 PM »
Write down reaction using molecular formula and balance it. The Knoevenagel–Michael reaction is a simple condensation with elimination of water. Your data suggests reaction with limiting reagent.
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Offline 58Fred

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Re: Balance this equation and determine theoretical yield?
« Reply #2 on: October 29, 2016, 07:51:51 PM »
Quote from: AWK on October 29, 2016, 07:42:47 PM
Write down reaction using molecular formula and balance it. The Knoevenagel–Michael reaction is a simple condensation with elimination of water. Your data suggests reaction with limiting reagent.

Okay:

What I have is

__(C8,H12,O2)+__(C7,H6,O) = (C23, H28, O4)


P.S.

I did a mechanism but I was just double checking here... I'd post it but I can't post pictures I believe.
I can see it's going to involve fractions.... and I'm having a hard time coming up with the correct numbers.
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Offline AWK

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Re: Balance this equation and determine theoretical yield?
« Reply #3 on: October 29, 2016, 07:53:07 PM »
No fractions, coefficients are only 1 and 2.
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Offline 58Fred

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Re: Balance this equation and determine theoretical yield?
« Reply #4 on: October 29, 2016, 08:00:29 PM »
Quote from: AWK on October 29, 2016, 07:53:07 PM
No fraction, coefficients are only 1 and 2.

__(C8,H12,O2)+__(C7,H6,O) = (C23, H28, O4)

I don't understand. As i see it, from my undergrad view, It has C 8 and C7 in the reagent side. According to you, you're claiming that 1*8 + 2*7 = 22 which is not equal to 23.
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Offline AWK

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Re: Balance this equation and determine theoretical yield?
« Reply #5 on: October 29, 2016, 08:03:27 PM »
Look at scheme at JChemEd and use correct combination of coefficients.
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Offline 58Fred

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Re: Balance this equation and determine theoretical yield?
« Reply #6 on: October 29, 2016, 08:13:14 PM »
Quote from: AWK on October 29, 2016, 08:03:27 PM
Look at scheme at JChemEd and use correct combination of coefficients.

I'm sorry...


I went back and added them up.... could you correct me?
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Offline AWK

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Re: Balance this equation and determine theoretical yield?
« Reply #7 on: October 29, 2016, 08:14:56 PM »
2*8 + 1*7
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Offline 58Fred

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Re: Balance this equation and determine theoretical yield?
« Reply #8 on: October 29, 2016, 08:18:51 PM »
Quote from: AWK on October 29, 2016, 08:14:56 PM
2*8 + 1*7

Haha!!!!

Thanks a lot, I had to reversed!

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Offline AWK

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Re: Balance this equation and determine theoretical yield?
« Reply #9 on: October 29, 2016, 08:40:46 PM »
One more comment
Molecular formula should be written in that way: C7H6O
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