intermolecular forces

Intermolecular forces

The attractive forces between neighboring atoms ions or molecules

Stronger intermolecular forces result in

Shorter intermolecular distances

Polarity

Result of uneven electron distribution due to differences in electronegativity

Dispersion force

The weakest of all the intermolecular forces

Constant motion of electrons

Polarization

The ease with which an atom or molecule can develop an instantaneous dipolar

A more polaraxible sample experiences

A stronger dispersion force

For substances with similar or identical molar masses an increase in

Surface area corresponds to an increase in polarizibilty

Dipole-Dipole force

The intermolecular force between two polar molecules

Hydrogen bonding

Arises when an elctropositive atom of hydrogen covalently bonded to a nitrogen oxygen or fluorine is attracted to an electronegative atom of nitrogen oxygen or fluorine in a neighboring molecule.

Stronger intermolecular forces correspond to

An increase in melting and boiling point.

Normal melting and boiling points

refer to the temperatures at a pressure of exactly 1 atm

Phase diagram

A graph of a substances pressure as a function of temperature

Triple point

The exact temperatures and pressure at which all three phases of solid liquid and gas are in equilibrium.

Critical point

Lies at the end of the liquid gas boundary, where a substance beyond its critical temperature and pressure is known as a supercritical fluid

Supercritical fluid

A phase of matter that exhibits properties of of both a liquid and a gas

The anomolous behavior of water, liquid not solid is favored at higher pressures where

A denser liquid allows ice to float