Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: bashir2008 on 10/04/2009 14:27:38
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Dear all
1- I want to understand more about Van der Waals force . how does it happen and what is the importance of it... could you please support your answer with some drawings as well?
2- What is the drag force ?
Hope there are some people who can assist me
Thanks
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Drag force is forces that oppose the relative motion of an object through a fluid (a liquid or gas).
http://en.wikipedia.org/wiki/Air_resistance
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For van der Waals:
http://www.chemguide.co.uk/atoms/bonding/vdw.html
Separate page for hydrogen bonding:
http://www.chemguide.co.uk/atoms/bonding/hbond.html#top
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Vander bonding easy to learn
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Obviously it is easier to learn it than to spell it? [:)]
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LOL [;D] [;D] Ya you are right
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Thanks for answering the question
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For van der Waals:
http://www.chemguide.co.uk/atoms/bonding/vdw.html
Separate page for hydrogen bonding:
http://www.chemguide.co.uk/atoms/bonding/hbond.html#top
Just for curiosity, why did you link the page of hydrogen bonding?
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In a textbook it (hydrogen-bonding) went under the same heading (as instantaneous dipole-dipole, permanent dipole-dipole etc...) of: van der Waals forces.
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In a textbook it (hydrogen-bonding) went under the same heading (as instantaneous dipole-dipole, permanent dipole-dipole etc...) of: van der Waals forces.
Ok, you can throw away that text [:)]. They are completely different things.
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Oh really? [???] That'll mean...have I been learning the wrong stuff? [:)]
So they are a completely different form of intermolecular attraction?
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Oh really? [???] That'll mean...have I been learning the wrong stuff? [:)]
So they are a completely different form of intermolecular attraction?
Yes:
Van der Waals interactions are much weaker (per unit surface of molecules) than hydrogen bonding and, furthermore, they are dipole interactions due to instantaneous dipole induction, whyle hydrogen bonding are due to permanent dipoles; furthermore hydrogen bonding is directional (just think about ice' structure), Van der Waals is not.
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Okay, I see what you mean. Cheers lightarrow.