Intermolecular forces are the forces of attractions or repulsion between molecules in a compound. Those attractions are more weak and less directional compared to covalent bonds and operate over a longer. These cause the compound to exist in a certain state of matter: solid, liquid, or gas; and affect the melting and boiling points of compounds.

Intermolecular forces are classified into the following categories:

• ion - dipole forces
• ion - induced dipole forces
• dipole - dipole forces
• dipole - induced dipole forces
• dispersion forces

Hydrogen bonds are usually listed as a type of dipole-dipole force. A necessary condition for hydrogen bonding is that one molecule must contain a H bonded to either N, O, or F; and the other molecule must contain either N, O, or F. Hydrogen bonding is responsible for unexpectedly different physical properties of compounds including the shape of many biological molecules , such as DNA and proteins.

• Intermolecular forces
• Hydrogen bonding
• Problems and tests

Intermolecular forces

http://www2.gasou.edu/chemdept/general/molecule/forces.htm Examples for intermolecular forces in ionic compounds, metals and covalent compounds.

http://www.chem.unsw.edu.au/UGNotes/hainesIMF/contents.html Types and classification of intermolecular forces.

http://wine1.sb.fsu.edu/chm1045/notes/Forces/Intermol/Forces02.htm Models of ion-dipole, dipole-dipole, London dispersion forces and hydrogen bonding.

http://chem.stthomas.edu/pages/genchem/data/ch10/ch10_02.htm Pictures, tables and graphics of different types intermolecular forces.

http://207.10.97.102/chemzone/lessons/03bonding/mleebonding/van_der_waals_forces.htm Animated example for van der Waals forces (also called London Dispersion Forces.

http://www.chemguide.co.uk/atoms/bonding/vdw.html#top Van der Waals and dipole-dipole interactions.

http://genchem.chem.wisc.edu/sstutorial/FunChem.htm Interactions between polar molecules (click on “Bonding” and after that on “Interactions”).

http://207.10.97.102/chemzone/lessons/03bonding/mleebonding/moleculeion_attractions.htm Animated visualisation of interactions between the water molecule and an ionic substance.

http://intro.chem.okstate.edu/1515SP01/Lecture/Chapter12/Lec2201.html Example for ion-dipole interaction - NaCl and water.

http://www.chem.purdue.edu/gchelp/liquids/iondip.html Visualisation of ion-dipole forces.

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Hydrogen bonding

http://207.10.97.102/chemzone/lessons/03bonding/mleebonding/hydrogen_bonds.htm Animated example for hydrogen bonding.

http://www.biology.arizona.edu/biochemistry/tutorials/chemistry/page3.html Hydrogen bonding between water molecules.

http://www.chem.purdue.edu/gchelp/liquids/hbond.html Formation and physical consequences of hydrogen bonding.

http://mdp2.phys.ucl.ac.uk/Talks/Ice/Ice.html Hydrogen bonding in ice.......

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Problems and tests

http://stimpy.chem.selu.edu/help/intermolecular_forces/test.html   Intermolecular forces and bonding.

http://colossus.chem.umass.edu/genchem/chem 112/MCQ_Intermolecular_Forces.htm Intermolecular forces and bonding.

http://www.mcgrawhill.ca/school/booksites/chemistry+12/ Intermolecular forces and bonding.

http://genchem.chem.wisc.edu/sstutorial/FunChem.htm   Intermolecular forces and bonding.

http://www.mcgrawhill.ca/school/booksites/chemistry+12/ Intermolecular forces and bonding.

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