
Liquids and solids review- Unit 2A
Melting and boiling points rise with the
-strength of IMFA
-increasing molar mass
Tyes of IMFFA’s
Covalent network
STRONGEST
Ionic bond
Elan Farhi and Jamie Elekman
Occurs between:
Atoms such as C, SI, GE (when in extended
grid network)
Cations and anions (metals with nonmetals
in a salt)
Metal atoms
Ultra polar molecules (H-F, H-O, H-N) bonds
Colligative Properties
Metallic bond
(depends on how many, but not what kind
Hydrogen bond (van
of, solute particles are present)
der waals forces)
(1) Elevation of boiling point
Dipole-dipole attraction Polar molecules
(van der waals forces)
(2) Raising the freezing point (physical
London forces (van der Nonpolar molecules
change)
(3) Osmotic pressure- tendency of unequal waals forces)
WEAKEST
concentrated solutions to support
necessary transport to make both sides the same. Need to be immersed.
Ex: trees fight gravity with osmotic pressure
CmolarRT= π
Ex: carrot in water
The greater concentration difference from the two, the greater the force pushing from one to another
Tf (b )  iC molalK f (b )
sucrose
NaCl
CaCl2
AlCl3
(photo from www.splung.com)
i (ideal).
(van’t Hoff
factor)
1
2
3
4
Molar concentrations and other concentration units
Cmolar= nsolute / vsolution
Cmolal= nsolute / masssolvent
Density= masssolution / vsolution
(Mole fraction) x = nsolute / ntotal solution
Tb  iK bCmolal
Tf  iK f Cmolal
Raoult’s Law:
Pvapor  x solventPvapor
Henry’s Law: Sg= KHPg (Sg= amt of gas
dissolved in water
mass%  masssolute /masssolute  masssolvent
x 100
KH= Henry’s law constant which
depends on solute/solvent/temp
Pg= pressure of the gas
Cubic Crystal Structures
simple cubic:
e=2r
8 atoms (1/8) = 1 atom
dense
body centered cubic:
4r= √3 e
8(1/2) + 1= 2 atoms
denser
v= e3 for all of the cubic structures
(image from http://users-phys.au.dk/philip/pictures/physicsfigures/node4.html)
face centered cubic
4r= √2e
8(1/2) + 6 faces (1/2) = 4 atoms
densest