INTERMOLECULAR FORCES Flashcards
The fundamental difference between states of matter is?
distance between particles
Types of states
liquid
gas
solid
Properties of a gas?
disorder
empty space
rapid diffusion
Properties of liquid?
Some disorder
particles move
some empty space (particles closer)
slow diffusion
Properties of solid?
ordered
no particle movement
no diffusion
What are the 2 factors the state of a substance depends on?
kinetic energy of particles
strength of attraction between particles
intermolecular vs intramolecular?
INTER-forces that exist BETWEEN molecules
INTRA-forces that exist WITHIN molecules
What is stronger? intermolecular forces or intra?
intramolecular forces are much stronger.
What force controls boiling point, viscosity, vapour pressure etc?
Intermolecular forces
Another term for intermolecular forces?
Van der waals forces
What does the strength of intermolecular forces depend on?
polarity
-more polar=stronger attraction between species
intermolecular forces are ?
inversely proportional to distance squared
What are ion-dipole forces?
attractive force resulting in electrostatic attraction between ion and neutral molecule with dipole.
responsible for ionic substances dissolving polar solvents
what are dipole-dipole forces?
partially negative ends of polar molecules are attracted to partially positive ends of nearby polar molecules
the more electronegative the element bound to hydrogen,
the greater the dipole moment, dipole-dipole interactions and mp&bp
What is hydrogen bonding?
primarily electrostatic force of attraction between a hydrogen atom which is covalently bound to a more electronegative atom
What are London-Dispersion forces?
weakest intermolecular force
all atoms/molecules are weakly attracted through L-D forces
present in ALL molecules
how does shape affect L-D forces?
long and skinny molecules have strong L-D forces compared to short and broad ones
as molecular weight increases
boiling point increases
Large molecules have?
more elcetrons=
large molecules = stronger dispersion forces= higher boiling points
More electrons= higher surface area= larger dispersion forces
what are the force strengths?
GREAT ionic bonding-Ion-dipole-hydrogen bonding-Dipole/dipole-Dispersion LEAST
