Brenda B.

asked • 09/09/12

why does covalent bonds determine the polarity of water?

Why does hydrogen bonds determine the water's special propeties?

George A.

Arthur,

Yeah, I should have looked up the angle instead of trusting my memory. But you do not understand that my description of the geometry of the water molecule is exactly equivalent to yours (except, of course, for the angle). I see a water molecule as 3 atoms in space, which are not collinear and, therefore, determine a plane and a triangle in that plane. If your picture of that triangle contains the two covalent bonds represented as lines, then it looks like a bent line as you describe it. However, I do not see the covalent bonds as lines connecting atoms but rather as sharing of electrons. The Tinker Toy model of a water molecule does not work for me.

By the way, the exact angle, as long as it is obtuse, plays no role at the level the questions that were presented. That's why I didn't bother to look it up.

My real concern about my answer is whether it is intelligible to Brenda. Without feedback I have no way to tell.

George

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09/11/12

Arthur S.

George,

I understand however the angle actually plays a role in explaining why there are excess charges at the oxygen and hydrogen ends of this molecule.  The angle allows the right amount for repulsion between the hydrogen atoms while minimizing the attraction of the hydrogen atoms by the oxygen atoms. The bond length itself is defined by this angle and thus the polarity. To put it simply, any angle larger than this or smaller (but neither is possible) would change the characteristics of the water molecule.  While I know this is far more than is required to make it intelligible it is key to understanding the water molecule.

Art

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09/11/12

4 Answers By Expert Tutors

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Truc N. answered • 09/18/12

Fun with chemistry

George A. answered • 09/10/12

Mathematics, Science, and English Language Tutor

Arthur S.

George,

Some misinformation has been supplied by you. First the orientation of water is a "bent" not triangle configuration as you described it. It is this bent formation that allows for the ease of rotation of the covalent bonds to form hydrogen bonds between water molecules or other species. Second, the angle between the oxygen and hydrogen is approximately 105°. No where near the 135° you metion.

Best Regards,

Art 

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09/11/12

Arthur S. answered • 09/09/12

Math, Science, Chemistry, and Computer Tutor

HANS P.

it is van der Waals forces that hold water molecules together not hydrogen bonds

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09/12/12

Joe C.

It is definitely Hydrogen bonds.
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12/12/14

Nicole C. answered • 09/09/12

Increase confidence in math and science, chemistry, algebra II

HANS P.

pretty good description of intramolecular attraction due to polarity

hans

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09/12/12

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