Intermolecular Forces Flashcards
(Intermolecular Forces) Hydrogen bonds?
Occurs between a hydrogen that is covalently bonded to fluorine, oxygen, or nitrogen and another F, O, or N with at least one lone pair.
(Intermolecular Forces) What makes one ionic compound dissolve and another not?
If sum of intermolecular forces is greater than than the sum of intramolecular forces, the ionic bond will dissolve.
A compound will dissolve if cation-anion attractions are weaker than ion-dipole attractions – large ions dissolve easier according to Coulomb’s Law.
(Intermolecular Forces) Hierarchy of Strength of Intermolecular Forces
- Ion-ion
- Ion-dipole
- H-bonds
- Dipole-dipole
- Ion-induced dipole
- Dipole-induced dipole
- London dispersion
(Intermolecular Forces) Ion-dipole?
The forces of attraction between an ion and a polar molecule (i.e. Na+ and Cl- dissolved in H2O).
(Intermolecular Forces) Dipole-dipole?
The attractive forces between the negative end of one polar molecule and the positive end of another polar molecule.
(Polarizability) The presence of Pi bonds…
increase polarizability.
(Polarizability) Polarizability and Melting/Boiling Point
The more polarizable a substance is, the higher the boiling/melting point.
Increase BP = Increase Polarizability
(Polarizability) The more electrons a species has the more…
polarizable it is.
(Polarizability) Geometry and Polarizability
Geometry that allows neighboring molecules to approach one another more closely will facilitate the formation of more and stronger induced dipoles.
Think: molecules look puzzle-piece-like? Less polarizable. Lower boiling point.
(Polarizability) Polarizability, Size, and Molar Mass
Larger or more massive the compound, the more polarizable it is.
(Miss.) Viscosity
A measure of a liquid’s resistance to flow: viscosity increases as strength of intermolecular forces increase.
(Misc.) Surface Tension
Stronger IMF = greater PE difference between interior and surface molecules = greater surface tension.
(Misc.) Capillary Action - Adhesion
Intermolecular forces between the liquid and the glass.
(Misc.) Capillary Action - Cohesion
Intermolecular forces between molecules in the liquid.
(Solids) Amorphous
No orderly structure; lack well defined faces and shapes.
Ex. Glass
