Friday, August 08, 2008

changed

i duno y after i come back.. the heptagon seems so different...

1 comment:

Chun! said...

i suppose you were the hydrogen bond that results from a dipole-dipole force between an electronegative atom and a hydrogen atom bonded to nitrogen, oxygen or fluorine (thus the name "hydrogen bond", which must not be confused with a covalent bond to hydrogen). The energy of a hydrogen bond (typically 5 to 30 kJ/mole) is comparable to that of weak covalent bonds (155 kJ/mol), and a typical covalent bond is only 20 times stronger than an intermolecular hydrogen bond. These bonds can occur between molecules (intermolecularly), or within different parts of a single molecule (intramolecularly).[2] The hydrogen bond is a very strong fixed dipole-dipole van der Waals-Keesom force, but weaker than covalent, ionic and metallic bonds. The hydrogen bond is somewhere between a covalent bond and an electrostatic intermolecular attraction. This type of bond occurs in both inorganic molecules (water) and organic molecules (DNA).

Intermolecular hydrogen bonding is responsible for the high boiling point of water (100 °C). This is because of the strong hydrogen bond, as opposed to other group 16 hydrides. Intramolecular hydrogen bonding is partly responsible for the secondary, tertiary, and quaternary structures of proteins and nucleic acids.

Thats why it seems different now that you're back.