CHEM STUDY GUIDE CH.12 : Liquids, Solids, and Intermolecular Forces

Changing a materials state requires …

changing the amount of kinetic energy the particles have or limiting their freedom

An intermolecular force is …

interactions between particles (molecules, ions, and atoms)

An intermolecular force is also…

weaker than chemical bonding

IMF’s ( intermolecular forces) govern certain properties such as …

state of a molecule, viscosity, vapor pressure, boiling point , & more

The structure of particles determine…

the strength of the intermolecular forces that hold a substance together (1st IMF rule)

The particles are attracted to each other by…

electrostatic forces (not a bond) (2nd IMF rule)

The intermolecular forces determine …

the state of the substance (3rd IMF rule)

With solids and liquids , relative short distances b/w particles means…

IMF’s are important

With Gases, relatively large distances b/w particles means…

IMF’s are negligible ( they don’t matter)

List the strength of intermolecular forces in order

ion-ion> ion dipole> hydrogen bond> dipole-dipole > dispersion

LDF ( London Dispersion Force) is …

a result of temporary instantaneous dipoles

All molecules have London dispersion forces but…

they are most important for non-polar molecules, hydrocarbons, & atomic species

LDF’s are …

the weakest intermolecular force

Larger and heavier atoms have stronger dispersion forces than smaller and lighter molecules due to…

the presence of a large electron cloud

EX of LDF’s) In water the strong the attractive forces among the molecules..

the higher the boiling point will be ( He;4.00g/gmol; 4.2(K) boiling point vs Xe; 131.30g/mol/ 165(K) boiling point