HYDROGEN+BONDING

__ **A hydrogen atom that is covalently bonded to one of N, O or F. - relatively strong dipole-dipole attraction (dipole force < hydrogen bonding < covalent bonds) - N, O and F are highly electronegative - one or more bonds are formed**  
 * What is a Hydrogen Bonding?** __

When does a Hydrogen Bond form? __ When the formula includes: a. HF (only example containing F-H) b. NH3, NH2 or NH (ex. CH3- NH2 , (CH3)2NH) c. H2o, H2O2, or OH (ex. CH3-OH)
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** H- F //- //H-F  - covalent bonds that hold H and F together //- // hydrogen bond <span style="font-family: 돋움; font-size: 10pt;"> <span style="font-family: 돋움; font-size: 14pt;">The diagram implies that the hydrogen bond is quite strong. The hydrogen bonds can hold adjacent molecules closely together. <span style="font-family: 돋움; font-size: 10pt;">
 * __<span style="color: purple; font-family: 돋움; font-size: 14pt;">EXAMPLE. __<span style="font-family: 돋움; font-size: 10pt;">

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 * <span style="font-family: 돋움; font-size: 14pt;">The diagrams below are the structures of ice <span style="display: block; font-family: Symbol,sans-serif; font-size: 110%; text-align: center;">[[image:ice_structure.gif width="183" height="173"]][[image:IceItop.gif width="178" height="167" align="right"]] **
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The following diagrams are the DNA structures that include hydrogen bonding. <span style="font-family: Symbol,sans-serif; font-size: 110%;"> ** Why is water the best example for the Hydrogen Bonding? __<span style="font-family: 돋움; font-size: 10pt;"> <span style="font-family: 돋움; font-size: 14pt;">- the oxygen end of a water molecule is negatively charged and the hydrogen end positively charged -> unlike charges attract each other!! ** Hydrogen bonding in alcohols __<span style="font-family: 돋움; font-size: 10pt;"> <span style="font-family: 돋움; font-size: 14pt;">An alcohol is an organic molecule containing an -O-H group. ** <span style="font-family: Symbol,sans-serif; font-size: 110%;"> <span style="color: #000000; font-family: Arial,Helvetica;">
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The compounds containing hydrogen bonds have high melting and boiling points. Because of hydrogen bonding, the intermolecular force in the compound becomes large. Therefore, larger energy is required to separate these molecules before they can melt or boil.
 * __<span style="color: purple; font-family: 돋움; font-size: 14pt;">How does the hydrogen bond influence melting point and boiling point? __**

References! http://en.wikipedia.org/wiki/Hydrogen_bond http://www.elmhurst.edu/~chm/vchembook/161Ahydrogenbond.html http://www.chemguide.co.uk/atoms/bonding/hbond.html http://staff.jccc.net/pdecell/chemistry/bonds.html http://www.tutorvista.com/content/chemistry/chemistry-iii/chemical-bonding/hydrogen-bonding-water-ice.php