Chem 1C Exam 2 UCSB

molality (m)

moles of solute/mass of solvent (kg)

volatile

highly unstable; explosive
has some vapor pressure; does evaporate to some extent
can evaporate and will contribute to the vapor pressure of a solution

nonvolatile

low vapor pressure at room temperature
ex: NaCl, KNO3, C6H12O6

adding a nonvolatile solute to a solvent

lowers the solvent's vapor pressure

Raolt's Law for a volatile solvent and a nonvolatile solute

Psolution = Xsolvent * Ppuresolvent

lower vapor pressure

higher boiling point, higher IMF

boiling point elevation

Adding a nonvolatile solute to a solvent lowers the vapor pressure of the solution, raising the boiling point of the resulting solution above that of the pure solvent

freezing point depression

Adding a nonvolatile solute to a solvent lowers the freezing point of the resulting solution below that of the pure solvent (need to remove more energy for the solution to freeze because nonvolatile solute prevents crystallization)

osmotic pressure

additional pressure needed to prevent or reverse osmosis

osmosis

diffusion of water across a selectively permeable membrane

IMF solution > IMF uncombined

strong solute-solvent interaction
process is exothermic (release energy/heat as a result form of bond formation)
Delta H for combination is a large negative, the overall change in enthalpy is negative (exothermic)

form IMF

release energy

break IMF

add energy

delta H (change in enthalpy) for expansion

positive (add energy)

Enthalpy

total energy of a system

delta H for combination

negative (release energy)

IMF solution < IMF uncombined

weak solute-solvent interaction
process is endothermic
Delta H for combination is a small negative, the overall change in enthalpy is positive (endothermic)

Delta H positive

endothermic

Delta H negative

exothermic

like dissolves like

polar dissolves polar
nonpolar dissolves nonpolar
ionic compounds ONLY dissolve in polar solutes

Entropy

A measure of disorder or randomness.

positive delta G

non-spontaneous

negative delta G

spontaneous

delta G

delta H - T delta S
T (in K) = always positive

positive delta S

like and like
more disordered

negative delta S

unlike and unlike
less disordered
ex: water and oil- water will arrange itself around the oil to avoid it

solubility of solids ____ as temperature increases

increases

solubility of gases ____ as temperature increases

decreases

Raolt's Law for a volatile solvent and a volatile solute

Pa = Xa Ppurea
Pb = Xb Ppureb
Psolution = Pa + Pb
Psolution= total vapor pressure of solution
assumes IDEAL solution (where IMFs do not play a factor)

Negative deviation from Raoult's law

IMF solution > IMF pure substances
lower vapor pressure than expected (ideal solution)
exothermic
solution feels warm

hydrogen bond donor

hydrogen directly bonded to a N, O, or F atom

hydrogen bond acceptor

any N, O, or F atom with lone pairs

Positive deviation from Raoult's law

IMF solution < IMF pure substances
high vapor pressure than is expected (ideal solution)
endothermic
solution feels cold

non-polar

hydrocarbons, or large hydrocarbons (4+ Cs) w/one O or N

for elements with 4 or 9 d-orbital electrons

move an electron from s orbital into d orbital

when forming metal cations

remove s orbital electrons first

complex ion

charged species consisting of transition metal ion surrounded by ligands

ligands

molecules or ions that bond to the transition metal ion in a complex ion

counter ions

Ions that balance charge. Not part of the complex ion.

ligands attach by

donating a lone pair to form a covalent bond with transition metal

lewis base

electron pair donor

lewis acid

electron pair acceptor

ligand attachment site

any atom with a lone pair
multiple attachment sites are possible only if there are 2+ atoms in between the atoms with lone pairs

coordination number

the number of bonds to the transition metal

CN = 2

linear

CN = 4

tetrahedral

CN = 6

octahedral

Splitting of d-orbitals for octahedral complexes

3 on the bottom, 2 on the top
bottom: xz, xy, yz
top: x^2 - y^2 , z^2

Splitting of d-orbitals for tetrahedral complexes

3 on the top, 2 on the bottom
bottom: x^2 - y^2 , z^2
top: xz, xy, yz
ALWAYS have weak field (high spin case)

weak field ligands

small delta E
Ligands that cause a small difference in the energies of d subshells
can populate top and bottom energy levels at the ground state (can add e- to the top before the bottom is completely full)

strong field ligands

large delta E
ligands that cause a large difference in the energies of the d subshells
can NOT populate the top and bottom energy levels at the ground state (can only add e- to the top once the bottom is completely full)

delta E (energy of absorbed photon)

hc/lamda (wavelength)

wavelength (lamda)

hc/delta E

you observe the _____ color of light absorbed by the complex

complementary

shorter wavelength

higher energy

diamagnetic

all electrons are paired (repelled by magnetic field)

paramagnetic

unpaired electrons (attracted to magnetic field)

H2O ligand name

aqua

NH3 ligand name

ammine

CO ligand name

carbonyl

NO ligand name

nitrosyl

anion ligands

drop suffix (-ide) and add -o

CO3 2- ligand name

carbonato

1

no prefix

2

di

3

tri

4

tetra

5

penta

6

hexa

Use greek prefixes when naming

ligands that already contain a prefix (ex: en)
write greek prefix then ligand name in parenthesis

1 (greek)

none

2 (greek)

bis-

3 (greek)

tris-

4 (greek)

tetrakis-

when complex ion is an anion

add -ate to the end of the metal name

Fe (in anionic complex)

ferrate

Cu (in anionic complex)

cuprate

Pb (in anionic complex)

plumbate

Ag (in anionic complex)

argentate

Au (in anionic complex)

aurate

Sn (in anionic complex)

stannate

Mo (in anionic complex)

molybdate

Isomer

Compounds with the same formula but different structures.

structural isomers

differ in the covalent arrangements of their atoms (different types of bonds)
ligands swap places in coordination compound
coordination isomers and linkage isomers

Stereoisomers

Compounds with the same structural formula but with a different arrangement of the atoms in space (same bonds, different spatial arrangements)
geometric and optical

linkage isomers

ligand is bound to the metal by a different atom (different binding site on the ligand)

cis (geometric isomer)

same ligands are side by side

trans (geometric isomer)

same ligands are across from each other

MX4X2

octahedral complex capable of forming cis/trans isomers

MX2X2

square planar/tetrahedral complex capable of forming cis/trans isomers

linkage isomers are possible when

there are two distinct attachment sites on ligands

geometric isomers are possible when

MX4Y2
MX2Y2

organic molecules

molecules that contain carbon

alkanes

CnH2n+2
saturated hydrocarbons, single bonds
always non-polar
low boiling points
low reactivity
suffix -ane

1 carbon

meth

2 carbons

eth

3 carbons

prop

4 carbons

but

5 carbons

pent

6 carbon

hex