chem 106 quiz 1 Flashcards
properties of a gas
no fixed shape
no fixed volume
compressible
diffusion rapid
properties of liquids
no fixed shape
fixed volume
incompressible
diffusion slower
properties of solids
fixed shape fixed volume incompressible molecules locked in place (bonds) diffusion extremely slow
boiling points can indicate
the strength of the intermolecular attractive force
ΔHfusion represents the phase change from
solid > liquid
ΔHvaporization represents the phase change from
liquid > gas
which is typically larger? ΔHfusion or ΔHvaporization? why?
ΔHvaporization because completely breaking attractive forces
intermolecular forces (from strongest to weakest)
ion-dipole
dipole-dipole (Hydrogen bonding)
dispersion
all molecules have ? forces
dispersion; strongest for nonpolar tho
? molecules have dipole-dipole forces
polar
ion-dipole forces are present in
mixtures of ionic compounds and polar compounds
surface tension and viscosity are affected by
intermolecular forces
dispersion forces are always weak in ? molecules but can be significant in molecules with ?
small; higher molar mass
Hydrogen bonds are present in molecules containing
hydrogen bonded directly to fluorine, oxygen, or nitrogen (but remember - hydrogen bonds are intermolecular/external)
the higher the temperature, the (lower/higher) the average kinetic energy of the collection of molecules
higher
ΔHvaporization is always (negative/positive) because the process is (endothermic/exothermic)
positive; endothermic
ΔHcondensation is always (negative/positive) because the process is (endothermic/exothermic)
negative; exothermic
boiling point
the temperature at which the liquid’s vapor pressure equals the external pressure
normal boiling point
the temperature at which its vapor pressure equals 1 atm
Clausius-Clapeyron equation
ln(P2/P1) = ( - ΔHvap / R) * ( 1/T2 - 1/T1)
the boiling point increases with increasing ? because of the high ?
ΔHvap; intermolecular forces
the pressure of vaporization (decreases/increases) with increasing IMFs and BP
decreases
reaction rates double every
10*C
solid to liquid
melting
liquid to solid
freezing
liquid to gas
vaporization
gas to liquid
condensation
gas to solid
deposition
solid to gas
sublimation
examples of crystalline solids
salt, diamond
examples of amorphous solids
glass, plastic, rubber
unit cell
smallest repeating unit from which you can build the whole crystal
cubic unit cell
cube with atoms on the vertices; 1 atom per unit cell
body centered cubic
cube with atoms on the vertices and one in the center; 2 atoms per unit cell
face centered cubic
cube with atoms on the vertices and in the centers of the faces; 4 atoms per unit cell (most efficient packing)
