Studied by 15 people
Condensed states
liquids and solids
intermolecular forces
forces of attraction between molecules
dipole-dipole attraction
intermolecular attraction between two permanent dipoles
Hydrogen bonding
intermolecular force in which a H atom that is bonded to a highly electronegative atom (N, O, F) is attracted to an unshared pair of electrons of an electronegative atom (N, O, F) in a nearby molecule
London Dispersion Forces (LDF)
The intermolecular attractions resulting from the constant motion of electrons distorting nearby electron clouds and creating temporary dipoles. (Always attractive)
Surface tension
The resistance of a liquid to an increase in its surface area -Direct relationship
capillary action
spontaneous rising of a liquid through a narrow tube against the force of gravity (Cohesive - attarcts to itself, Adhesive - Attracts to other substance) -Direct relationship
Viscosity
A liquid's resistance to flowing (thickness) -Direct relationship -increases with molecular complexity
crystalline solid
A solid that is made up of crystals in which particles are arranged in a regular, repeating pattern
Amorphus solid
A solid made up of particles that are not arranged in a regular pattern
Lattice
3D system of points designating the positions of the centers of the components of a solid
Unit cell
the smallest repeating unit of a lattice
X-ray diffraction
an analytical method in which X-rays change direction on contact with matter, resulting in changes in radiation intensity, that is used to determine the three-dimensional arrangement of atoms.
ionic solid
A solid consisting of ions at the points of the lattice
molecular solid
a solid composed of covalently bonded molecules at the lattice points
atomic solid
a solid that contains atoms at the lattice points
Band model (Molecular orbital (MO) model)
a molecular model for metals in which the electrons are assumed to travel around the metal crystal in molecular orbitals formed from the valence atomic orbitals of the metal atoms
Alloy
a combination; a mixture of two or more metals
substitutional alloy
some of the host metal atoms are replaced by other metal atoms of similar sizes
interstitial alloy
a mixture formed when small atoms fill holes in a metallic crystal
Network solid
atomic solids containing strong directional covalent bonds to form a solid that might best be viewed as a "giant molecule."
Silica
the fundamental silicon-oxygen compound, which has the empirical formula SiO2, and forms the basis of quartz and certain types of sand
Glass
An amorphous solid obtained when silica is heated above its melting point (1600°C) and cooled rapidly
semiconductor
A substance that can conduct electricity under some conditions
Insulator
A material that does not allow heat or electrons to move through it easily.
n-type semiconductor
a substance whose conductivity is increased by doping it with atoms having more valence electrons than the atoms in the host crystal
p-type semiconductor
a semiconductor that employs positively charged "holes" in the valence band as the charge carriers
p-n junction
a connection between a p-type semiconductor and an n-type semiconductor
vaporization (evaporation)
the change in state that occurs when a liquid becomes a gas _____________ (boiling) occurs when the vapor pressure of the liquid is equal to the pressure of the atmosphere
enthalpy of vaporization (ΔHvap) or heat of vaporization
The energy required to vaporize 1 mole of a liquid at a pressure of 1 atm
Condensation
The change of state from a gas to a liquid
Equilibrium
a state in which opposing forces or influences are balanced.
vapor pressure
the pressure of the vapor present at equilibrium
Sublimation
A change directly from the solid to the gaseous state without becoming liquid
Heating curve
a plot of temperature versus time for a substance where energy is added at a constant rate
enthalpy (heat) of fusion (ΔHfus)
The enthalpy change that occurs at the melting point when a solid melts
Normal melting point
the temperature at which the solid and liquid states have the same vapor pressure under conditions where the total pressure is 1 atmosphere
Normal boiling point
the temperature at which the vapor pressure of a liquid is exactly 1 atm
Supercooled
the process of cooling a liquid below its freezing point without its changing to a solid
Superheated
the process of heating a liquid above its boiling point without it boiling
Phase diagram
A graph of pressure versus temperature that shows the conditions under which the phases of a substance exist
Triple point
the temperature and pressure conditions at which the solid, liquid, and gaseous phases of a substance coexist at equilibrium
Critical temperature
the temperature above which a substance cannot exist in the liquid state
Critical pressure
the lowest pressure at which a substance can exist as a liquid at the critical temperature
Critical point
the temperature and pressure at which the gas and liquid states of a substance become identical and form one phase
Types of Van der Waals interactions
LDF’s, dipole-induced dipole, dipole-dipole, H-bonds, Ion-dipole
Stronger intermolecular forces creates ____________
Higher melting and boiling points, as well as higher enthalpies of fusion and vaporization
Strength of LDFs depends on..,
Polarizability of the electron cloud and the shape of the molecule When a molecules surface area is higher, there is greater opportunity for induced dipoles
dipole-induced dipole
The partial charge on a polar molecule induces a temporary partial charge on a neighboring nonpolar molecule or atom (Always attractive)
London dispersion forces Dipole-induced dipole Dipole-dipole H-bonds Ion-dipole forces
Relative strengths of all intermolecular forces
ion-dipole forces
attractive forces between an ion and a polar molecule
the pressure of a vapor in equilibrium with its liquid or solid form Stronger _____ result in lower ________ ___________
IMFs
Vapor pressure
Vaporization @ boiling point Vaporization below boiling point
boiling evaporation
Volatility
a measure of how readily a substance vaporizes -Inverse relationship
Miscible
Describes two liquids that are soluble in each other
