Intermolecular Forces of Attraction - PowerPoint PPT Presentation

intermolecular forces of attraction n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Intermolecular Forces of Attraction PowerPoint Presentation
Download Presentation
Intermolecular Forces of Attraction

play fullscreen
1 / 13
Intermolecular Forces of Attraction
128 Views
Download Presentation
hina
Download Presentation

Intermolecular Forces of Attraction

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Intermolecular Forces of Attraction AP Chemistry 2 SNSH Spring 2000

  2. Kinetic Molecular Theory • All matter is composed of atoms that are in constant motion

  3. Kinetic Theory Facts • All phases of matter express the degree that they reflect the kinetic theory through their kinetic energy • kinetic energy is measured by temperature • phase changes involve changes in temperature due to the existence threshold temperature of each phase (i.e. ice naturally is found at cold not hot temperatures)

  4. While gases have a great deal of random motion, solids and liquids exist at lower temperatures, thus allowing other forces of attraction to act upon them • these forces are the van der Waals forces

  5. Definitions • Bonds are intramolecular forces of attraction • Forces of attraction between molecules are called intermolecular forces of attraction • intermolecular forces of attraction are commonly called van der Waals forces

  6. The Condensed Phases • Solids and Liquids • Physical properties of the condensed phases reflect the degree of intermolecular forces (i.e. boiling point)

  7. Dipole-dipole forces • Exist between neutral polar molecules • work best the closer the molecules are to each other • the greater the polarity of the molecules, the greater the force of attraction

  8. H bonding • Special case of dipole-dipole interaction specifically between H of one polar molecule with N, O or F and an unshared electron pair of another nearby small electronegative ion (usually N, O, or F on another molecule) • VERY STRONG

  9. London dispersion forces • Induced dipoles • not really dipoles on the AVERAGE, but instantaneously dipole conditions can exist thus allowing for pseudopolar regions to occur

  10. No matter how strong the van der Waal force of attraction is, it is still not stronger than attractions involving ions

  11. Ion-dipole forces • Attraction between ions and the partial charge on the end of a polar molecule • ex. NaCl in water solution