(Gen Chem 2) Chapter 11: intermolecular forces

Dipole-Dipole interactions

Attraction between polar molecules

Vapor Pressure

pressure exerted by vapor in equilibrium with the liquid or solid phase

Low Vapor pressure

coincides with high boiling point; water has a low vapor pressure; slower evaporation; molecules with low vapor pressure have greater intermolecular forces.

Condensation

conversion of vapor to a liquid

Vaporization boiling point

point of boiling, point of turning to vapor

Surface Tension

intermolecular, cohesive attraction causing surface area of liquid to be minimized

Adhesion

attraction of particles for different substances (ex: water's attraction for glass walls of graduated cylinder)

Polarity

uneven distribution of electron density resulting in full or partial charge

Capillary Action

movement of liquid through a tube by force of adhesion and cohesion

Viscosity

measure of internal friction of liquids; resistance of a fluid to a change in shape. Higher viscosity has a greater intermolecular forces

Sublimation

changing from solid phase to gas phase without going through the liquid phase.

Deposition

changing from a gas to a solid without going through the liquid phase; opposite of sublimation

meniscus

curved upper surface of a liquid in a tube

Coordination Number

number of neighbor atoms for a central atom

ion-dipole force

attractive forces from the electrostatic attraction between an ion and a neutral molecule with a dipole

London Forces

attractive forces that causes no pole substances to condense to liquids and to freeze into solids when the temperature is lowered sufficiently

Dispersion Forces

Type of van der Waals force (weakest of all forces); London forces

Hydrogen Bonding

bonding that results from intermolecular attractions between molecules containing hydrogen bonded to an electronegative element - OH, NH, and HF

Molar heat of vaporization

energy needed to vaporize one mole of a liquid

intermolecular forces

attractive forces between molecules

Van Der Waals

weakest of forces; attraction and repulsions between atoms, molecules, and surfaces; forces formed polarizing of charges within atom or molecule.

Which substances will have hydrogen bonding?

Molecules containing oxygen, nitrogen, and fluorine are ideal for hydrogen bonding; alcohols

Will a substance have a dipole-dipole forces or dispersion forces?

Dipole-dipole forces are between polar substances.

Dispersion forces are present between molecules (all molecules)

How do the properties — strong intermolecular forces, temperature, hydrogen bonding, molecular entanglements, and London forces relate to viscosity?

Viscosity decrease with higher temperatures and increases with lower temperature. The stronger the intermolecular forces, then the greater the viscosity.

Relationship between boiling point and vapor pressure and external pressure

the higher the vapor pressure, then the lower normal boiling point will be. Temperature for boiling point is at the point that the vapor pressure is at 1 atmosphere