Intermolecular Intramolecular
Condensed States of Matter
held together by intermolecular forces
VSBETWEEN MOLECULES KEEPS MOLECULE TOGETHER
When something undergoes a phase change, the changes occur in the intermolecular forces.
Dipole-Dipole Forces
Occurs between two polar molecules
HYDROGEN BONDING
Strong form of dipole-dipole attractionsOccurs in molecules with hydrogen that is bonded with an element with a high E.N.High difference in electronegativity & small size contributes to its great strength
London Dispersion
ForcesOCCURS BETWEEN 2 NON-POLAR MOLECULES
INSTANT-ANEOUS DIPOLES IN LARGE
ATOMS, CAN BE MORE SIGNIFICANT THAN DIPOLE-DIPOLE FORCES
The Liquid State
measure of liquid’s resistance to flow
surface tension the resistance of a liquid to an increase in its surface area
capillary action spontaneous rising of a liquid in a narrow tube a result of adhesion and cohesion
Concave shape of meniscus shows adhesive > cohesive
Viscosity:adhesive versus cohesive
liquid particles attracted to themselvesforce between liquid and surrounding
describes the locations of the pieces in a crystalline solid
CRYSTALLINE SOLIDS
LATTICE
UNIT CELL smallest repeating unit of the lattice
as apposed to amorphous solids…
ATOMIC SOLIDS
atoms at lattice points
Metallic SolidsPositively charged & held together by neutrons.
Delocalized electron sea theory
Types of Crystalline Solids
ATOMIC SOLIDS
atoms at lattice points
Network SolidsAtoms bond covalently in a continuous network.
Strong Bonds -> High mp & bp Do not conduct electricity
Types of Crystalline Solids
ATOMIC SOLIDS
atoms at lattice points
Group 8A SolidsNoble gases bonded with London Dispersion
ForcesOccur at very low temperatures!
Types of Crystalline Solids
MET
ALS
It’s ductile!
It’s malleable!
strong & nondirectional
ELECTRON SEA MODEL
metal cations in valence e-
conduct heat and electricitymalleable and ductile
Diamond
Graphite
VERSUS
Hardest naturally occurring substance
sp3 hybridization
large gap between filled and empty levels in
energy diagram
carbon surrounded by a tetrahedral
Slippery, black, & a conductor
Layers of carbon atoms in 6 member rings
sp2 hybridization
weak bonding between layers accounts for
slippery texture
PHASE CHANGES
Heat of VaporizationENERGY NEEDED TO VAPORIZE A MOLE OF LIQUID
When does a liquid boil?its vapor pressure
EQUALSpressure of the environment
CLAUSIUS-CLAPEYRON EQUATION
1
2
vap, vap
vap, 2 1
1 1ln =
T
T
P H
P R T T
ΔHvap = enthalpy of vaporizationR = 8.3145 J/K·molT = temperature (kelvin)C=constant
Determine heat of vaporization, and can also be used to find
Pvap
Rate of Condensation and Evaporation
Rate of evaporation
remains constant while rate of condensation increases as number of
molecules in vapor phase increases,
until they become equal, and thus
reach equilibrium.