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Series: Chemistry: Intermolecular Forces


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About this Series

  • Lessons: 2
  • Total Time: 0h 29m
  • Use: Watch Online & Download
  • Access Period: Unlimited
  • Created At: 10/22/2009
  • Last Updated At: 07/20/2010

This is a two part series that will cover intermolecular forces. Our first lesson will fittingly be an introduction to intermolecular forces and states of matter. The state of a substance depends on the energy of the system and attractive forces between molecules. There is a distribution of energies in the molecules of a sample. At higher temperatures, more molecules have enough kinetic energy to leave the liquid phase and move into the gas phase. If the attractive forces between molecules are weak, more molecules will have sufficient energy to move out of the liquid phase. The intermolecular forces exhibited by a molecule are influenced by its dipole moment. In general, the stronger the dipole moment, the more energy required to change phases from liquid to gas. The direction of a phase change is reversible, depending on whether energy is added to or removed from the system.

After that introduction we will examine in greater detail intermolecular forces. The types of intermolecular attractions exhibited by a substance yield many clues to the behavior of the substance. The strongest types of intermolecular attractions are ion-ion attractions (or charge-charge attractions), in which oppositely charged particles are attracted to one another. In ion-dipole attractions, a charged particle attracts a molecule with a dipole moment. Dipole-dipole attractions involve the alignment of molecular dipole moments such that the opposing poles are in proximity. London forces (or dispersion forces) are weak intermolecular attractions between nonpolar molecules. Hydrogen bond donors contain hydrogen bonded to a very electronegative atom, and hydrogen bond acceptors have lone pairs electrons.

This series of lessons was selected from a broader, comprehensive course, Chemistry. This course and others are available from Thinkwell, Inc. The full course can be found at The full course covers atoms, molecules and ions, stoichiometry, reactions in aqueous solutions, gases, thermochemistry, Modern Atomic Theory, electron configurations, periodicity, chemical bonding, molecular geometry, bonding theory, oxidation-reduction reactions, condensed phases, solution properties, kinetics, acids and bases, organic reactions, thermodynamics, nuclear chemistry, metals, nonmetals, biochemistry, organic chemistry, and more. The course features three renowned chemistry professors: Dean Harman, a professor of Chemistry at the University of Virginia and Gordon Yee, an associate professor of Chemistry at Virginia Tech and Tarek Sammakia, a professor of chemistry at the University of Colorado at Boulder.

About this Author

2174 lessons

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Thinkwell lessons feature a star-studded cast of outstanding university professors: Edward Burger (Pre-Algebra through...

Lessons Included

None of the lesson in this series have been reviewed.

Below are the descriptions for each of the lessons included in the series:

Supplementary Files: