Do we need to know exact bond angles?

(Polar molecules, Non-polar molecules, etc.)

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Belicia Tang 1B
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Joined: Wed Sep 21, 2016 3:00 pm

Do we need to know exact bond angles?

Postby Belicia Tang 1B » Fri Oct 28, 2016 12:31 pm

If I recall correctly, in Wednesday's lecture, Dr. Lavelle said we don't need to memorize the exact bond angles. Is this correct? (b/c in the textbook problems a lot of questions ask us to predict bond angles based on molecular geometry...)




Thanks!

Brandon_Phan_3J
Posts: 21
Joined: Wed Sep 21, 2016 2:56 pm

Re: Do we need to know exact bond angles?

Postby Brandon_Phan_3J » Fri Oct 28, 2016 1:51 pm

I think what Prof. Lavelle said was that we didn't need to know exact bond angles but we should be able to predict if they're greater or less than the common bond angles (90°,120°,180°). Hope that helps!

Ann Zhang_1M
Posts: 25
Joined: Wed Sep 21, 2016 2:59 pm

Re: Do we need to know exact bond angles?

Postby Ann Zhang_1M » Sat Oct 29, 2016 1:13 pm

I don't think we need to know the exact values of bond angles. But we should be able to compare two bond angles when different molecular structures are given...

Chem_Mod
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Re: Do we need to know exact bond angles?

Postby Chem_Mod » Sat Oct 29, 2016 2:37 pm

Brandon_Phan_3J wrote:I think what Prof. Lavelle said was that we didn't need to know exact bond angles but we should be able to predict if they're greater or less than the common bond angles (90°,120°,180°). Hope that helps!


Correct.

As I discussed and showed in class many times:
VSEPR gives us the common bond angles (90°,120°,180°), and greater or less than the common bond angles (90°,120°,180°). Students are expected to know these.

VSEPR does not give us specific angles such as 104.5° for water. Students are not expected to know these individual, unique angles for molecules.


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