CHEM 0110: Final Exam Review
36 Cards in this Set
| Front | Back |
|---|---|
|
change of state/ phase transition
|
a change of a substance from one state to another
|
|
melting/ fusion
|
the change of a solid to the liquid state
|
|
freezing
|
the change of a liquid to the solid state
|
|
vaporization
|
the change of a solid or a liquid to the vapor
|
|
sublimation
|
the change of solid (only!) DIRECTLY to the vapor
|
|
condensation
|
the change of a gas to EITHER the liquid or solid state
|
|
deposition
|
the change of a vapor/ gas to a solid ONLY
|
|
vapor pressure (of a liquid)
|
the partial pressure of the vapor over the liquid, measured at equilibrium at a given temperature.
If a liquid is in a closed vessel with a space above it, vapor pressure BUILDS UP in the space.
|
|
boiling point
|
the temperature at which the vapor pressure of a liquid equals the pressure exerted on the liquid (atmospheric pressure, unless the vessel containing the liquid is closed)
Remember: you can increase vapor pressure via raising temperature!
Because the pressure exerted on a liquid can…
|
|
freezing point
|
the temperature at which a pure liquid changes to a crystalline solid, or freezes
This temperature is identical to the melting point
|
|
melting point
|
the temperature at which a crystalline solid changes to a liquid, or melts
this temperature is identical to the freezing point
|
|
heat of fusion/ enthalpy of fusion
|
the heat needed for the melting of a solid, denoted as ΔHfus
|
|
heat of vaporization/ enthalpy of vaporization
|
the heat needed for the vaporization of a liquid; denoted as ΔHvap
|
|
phase diagram
|
a graphical way to summarize the conditions under which the different states of a substance are stable
|
|
triple point
|
the point on a phase diagram representing the temperature and pressure at which three phases of a substance coexist in equilibrium
|
|
critical temperature
|
the temperature ABOVE which the liquid state of a substance no longer exists regardless of the pressure
|
|
critical pressure
|
the vapor pressure AT the critical temperature
It is the MINIMUM pressure that must be applied to a gas AT the critical temperature to liquefy it
|
|
intermolecular forces
|
the forces of interaction between molecules
|
|
van der Waals forces
|
a general term for those intermolecular forces that include dipole-dipole and London forces
|
|
dipole-dipole force
|
an attractive intermolecular force resulting from the tendency of POLAR molecules to align themselves such that the positive end of one molecule is near the negative end of another
|
|
London (dispersion) forces
|
the weak attractive forces between molecules resulting from the small, instantaneous dipoles that occur because of the varying positions of the electrons during their motion about the nuclei
These forces tend to increase as molecular mass increases
|
|
hydrogen bonding
|
a weak to moderate attractive force that exists between a hydrogen atom covalently bonded to a very electronegative atom, X, and a lone pair of electrons on another small, electronegative atom, Y.
--X--H . . . Y--
Usually, H-bonding is seen in cases where X and Y are atoms: F, O, or…
|
|
molecular solid
|
a solid that consists of atoms or molecules held together by intermolecular forces; many solids are of this type
ie. solid neon, solid water (ice), solid CO2 (dry ice)
|
|
metallic solid
|
a solid that consists of positive cores of atoms held together by a surrounding "sea" of electrons (metallic bonding)
In this kind of bonding, positively charged atomic cores are surrounded by delocalized bonds
ie. Fe, Cu, Ag
|
|
ionic solid
|
a solid that consists of cations and anions held together by the electrical attraction of opposite charges (ionic bonds)
ie. CsCl, NaCl, ZnS (but ZnS has considerable covalent character)
|
|
covalent network solid
|
a solid that consists of atoms held together in large networks OR chains by covalent bonds
ie. diamond, asbestos, graphite
|
|
crystalline solid
|
composed of one or more crystals; each crystal has a well defined ordered structure in three dimensions
ie. NaCl and sucrose (table sugar)
|
|
amorphous solid
|
has a disordered structure; it lacks the well-defined arrangement of basic units (atoms, molecules, or ions) found in a crystal
ie. glass (glass blowing! Makes sense!)
|
|
crystalline lattice
|
the geometric arrangement of lattice points of a crystal, in which we choose one lattice point at the same location within each of the basic units of the crystal
crystal lattice is NOT the same as a crystal structure
Many different crystals have the same crystal lattice
|
|
unit cell (of a crystal)
|
the smallest boxlike unit (each box having faces that are parallelograms) from which you can imagine constructing a crystal by stacking the units in three dimensions
|
|
simple cubic unit
|
a cubic unit cell in which lattice points are situated ONLY at the corners
|
|
body-centered cubic unit cell
|
a cubic unit cell in which there is a lattice point at the center of the cubic cell in ADDITION to those at the corners
|
|
face-centered cubic unit cell
|
a cubic unit cell in which these are lattice points at the centers of EACH face of the unit cell in ADDITION to those at the corners
|
|
hexagonal close-packed structure (hcp)
|
the result of the ABABABABA layering; a crystal composed of close-packed atoms (or other units) with the stacking ABABABA
the structure has a hexagonal unit cell
|
|
cubic close-packed structure (ccp)
|
a crystal structure composed of close-packed atoms (or other units) with the stacking ABCABCABCABC
This is identical to the lattice having a face-centered cubic unit cell
coordination number is 12
|
|
coordination number
|
the number of nearest-neighbor atoms of an atom
|
CHEM 0110: Exam 2