Solids & Liquids
NM Standards
 Students know the atoms and molecules
in liquids move in a random pattern
relative to one another because the
intermolecular forces are too weak to
hold the atoms or molecules in a solid
form.
Intermolecular Forces
Forces of attraction between
different molecules rather than
bonding forces within the same
molecule.
Dipole-dipole attraction
Hydrogen bonds
Dispersion forces
Forces and Phases
o Substances with very little
intermolecular attraction exist as gases
o Substances with strong intermolecular
attraction exist as liquids
o Substances with very strong
intermolecular (or ionic) attraction exist
as solids
Phase
Differences
Solid – definite volume and shape; particles packed in fixed positions;
particles are not free to move
Liquid – definite volume but indefinite shape; particles close together but
not in fixed positions; particles are free to move
Gas – neither definite volume nor definite shape; particles are at great
distances from one another; particles are free to move
Three Phases of Matter
Types of Solids
Crystalline Solids: highly regular arrangement of
their components [table salt (NaCl), pyrite (FeS2)].
Unit Cell
The smallest portion of a crystal lattice that
shows the three-dimensional pattern of the
entire lattice
Types of Solids
Amorphous solids:
considerable
disorder in their
structures (glass
and plastic).
States of Matter
Heating/cooling curve for water
Heating curve
Cooling Curve
Heating and Cooling curves
 Phase changes occur where the temperature stays
flat.
 After a phase change is complete and all molecules
are in the same state the temperature increases to
the next phase change.
Phase Diagram
 Critical point:
The vapor-liquid critical point denotes the conditions
above which distinct liquid and gas phases do not exist.
 Triple point: Where all phases coexist in a stable
equilibrium
 Normal freezing and boiling points occur at 1 atm
pressure read off the diagram