fayevalentine

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I thought that the carbon was sp3 hybridized, as it is attached to 3 C's and 1 H. Can someone please help me figure this out? I answered that the bond angle would be 109.5 for sp3, but the answer is 120. Why is this sp2? Thank you!

 
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To find the hybradization, I used to count the number of bonds (Keeping in mind that a double bond only counts as 1) and take away 1. so for Carbon#1 starting from the rigth, We have 1 hydr0gen bond, 1 carbon bond, and 1 oxygen bond = 3 bonds -1= SP2
Remember that because of resonance, the oxygen could very well have 1 single bond with 7 electrons DIRECTLY around it. I wish I could draw it for you but yeah.
 
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fayevalentine

fayevalentine

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To find the hybradization, I used to count the number of bonds (Keeping in mind that a double bond only counts as 1) and take away 1. so for Carbon#1 starting from the rigth, We have 1 hydr0gen bond, 1 carbon bond, and 1 oxygen bond = 3 bonds -1= SP2
Remember that because of resonance, the oxygen could very well have 1 single bond with 7 electrons DIRECTLY around it. I wish I could draw it for you but yeah.
Thank you! So my mistake I guess was that I was looking at hybridization on the carbon to the left of the one you indicated? How did you know to look at the right-most carbon? It looks like the angle is asking for the one to the left of it?
 
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Actually, now that I look at it again, it does look like they're asking for carbon #2 starting from the right. lol. MY BAD
If the answer is 120, I would have gotten it wrong as well. Ask your professor if he/she made a mistake. I would have said Sp3 for that one. ANYONE?
 
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fayevalentine

fayevalentine

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Actually, now that I look at it again, it does look like they're asking for carbon #2 starting from the right. lol. MY BAD
If the answer is 120, I would have gotten it wrong as well. Ask your professor if he/she made a mistake. I would have said Sp3 for that one. ANYONE?
Lol, I wish this was from a class but it's on the 2009 DAT! :shrug:
 

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View attachment 207701
I thought that the carbon was sp3 hybridized, as it is attached to 3 C's and 1 H. Can someone please help me figure this out? I answered that the bond angle would be 109.5 for sp3, but the answer is 120. Why is this sp2? Thank you!

Carbon 1 is sp2...carbon 2 is sp3......They are asking for the angle........ The area indicated is above these two carbons.....would be closest to 120........if it was a single bond bt C1 and C2,,,,,,,,it would be 109......but the double bond causes the angle to go wider,,,,,,,try building a model and see for yourself.

Hope this helps.

Dr. Romano

sdn.jpg
 
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fayevalentine

fayevalentine

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View attachment 207701

Carbon 1 is sp2...carbon 2 is sp3......They are asking for the angle........ The area indicated is above these two carbons.....would be closest to 120........if it was a single bond bt C1 and C2,,,,,,,,it would be 109......but the double bond causes the angle to go wider,,,,,,,try building a model and see for yourself.

Hope this helps.

Dr. Romano

View attachment 207702
Hi Dr. Romano, thank you very much for your answer. I am slightly confused though because there is no double bond between C1 & C2, so is it the double bond on the oxygen that is making the answer 120 instead of 109.5?
 

orgoman22

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Hi Dr. Romano, thank you very much for your answer. I am slightly confused though because there is no double bond between C1 & C2, so is it the double bond on the oxygen that is making the answer 120 instead of 109.5?
That is correct......it renders the carbon sp2.

Look at the pic.....it gives a better perspective of the 120 degree angle.

butanal.jpg
 
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That is correct......it renders the carbon sp2.

Look at the pic.....it gives a better perspective of the 120 degree angle.

View attachment 207704
Hi Dr. Romano, i am struggling with this same question, the question is referring to carbon #2 correct? and it is SP3 hybridized which would normally be 109.5 but since it is next to a carbon that is double bonded to and oxygen (carbon 1) it becomes a wider bond angle of 120???
 
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