INTERMOLECULAR FORCES are the forces which exist between molecules. They are the result
of the INTERMOLECULAR FORCES of individual ions or molecules interacting with other ions or
molecules. MOLECULAR/ATOMIC WEIGHT and POLARITY are the largest contributing factors to
the properties of melting point, boiling point, vapor pressure, viscosity, and surface tension. The effects of polarity
according to bond type and interaction
are ranked from highest to lowest: IONIC > ION-DIPOLE > H-BONDING>
DIPOLE-DIPOLE > LONDON DISPERSION. All compounds will exhibit LONDON DISPERSION interactions
since this is only dependent on the mass and distance the atoms or molecules are from each other. All other
interactions occur ONLY when there is a significant [>=1.5] difference in electronegativity.
Similarly the trend goes from METAL-NONMETAL > SEMIMETAL-NONMETAL>NONMETAL-NONMETAL
in bonding strength and difference in electronegativity. IONIC BONDING occurs when there is a total loss
and gain of electrons to form a bond. All types of COVALENT bonding results from the sharing of elections.
H-BONDING is a special type of dipole interaction that only occurs then O, N, or F are bonded to H.
HEAT/COOLING CURVES show how the addition of heat affects the temperature of a substance.
PHASE TRANSITIONS are a constant temperature since each requires that equilibrium is occurring and
that the heat of the transition will still control the system until only one phase exists. When only one
phase exists, then the specific heat capacity controls the rise or fall in temperature.
PHASE DIAGRAMS are plots of Temp vs Press which show how all three states, solid, liquid and gas
exists for a substance under various conditons. The EQUILIBRIUM
LINES lines drawn on a phase diagram show where each phase transiton occurs. The TRIPLE POINT
is the point where solid, liquid and gas are all in equilibrium with each other. The CRITICAL POINT is
the upper limit of Temp and Press at which liquid and gas phases are distinguishible from each other.
A UNIT CELL is the simplest representation of a crystal. Many basic crystal UNIT CELLs exist for solids.
The simples unit cells are CUBIC. SIMPLE CUBIC, BODY CENTERED CUBIC, AND FACE CENTERED
CUBIC unit cells are some of these.
INTERMOLECULAR FORCES
GA SOUTHERN
U IDAHO
FSU INTEMOLECULAR
sample test UMR
DR COMBS
HEAT/COOLING CURVES AND PHASE DIAGRAMS
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CUBIC CRYSTAL UNIT CELLS
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REED SEVEN UNIT CELL TYPES
OKLAHOMA STATE Intro Cubic Crystal...
RICE U UNIT CELL LAB
http://www.ill.fr/dif/3D-crystals/index.html