ch 19 Flashcards
deviations from raoult’s law
list the /possible interactions
no interactions
unfavorable interactins(repulsion)
favorable interactions
deviations from raoult’s law
no interactions =
ideal solution; two nonpolars
VP is as expected
delta H = 0
deviations from raoult’s law
unfavorable interactions
repulsions
one pushes other out of the solution –> gas
polar+ nonpolar
VP is higher than expected, positive deviation
delta H = positive –> endothermic
deviations from raoult’s law
favorable interactions
solution interactions are stronger than components
more interactions as a solution
“keep” components in solution
VP lower than expected
delta H negative –> exothermic
complex ion
transition metals surrounded by ligands
covalent bond between transition metals and ligands
transition metal is e- acceptor
ligands are e- donors
[Co(NH3)6] (NO3)3
label the components
[Co(NH3)6]NO3)3 = coordination compound
[Co(NH3)6] = complex ion
Co = transition metal
NH3 = ligand
NO3 = counter ion
counter ion and complex ion connected by ionic bond –> break in solution
coordination number
bonds to central transition metal
types of ligands
ligands must have a lone pair
neutral = NH3 and H2O
charged= Cl-
monodentate
polydentate
coordination number and relative shape
2= linear
4= tetrahedral or square planar
6 = octahedral
monodentate vs polydentate
monodentate = one binding site for ligand ( one transition metal to bind to)
polydentate = more than 1 bonding site
- polydentate must have multiple lone pairs and at least 3 to 4 atoms between lone pair bonding sites of ligands
ethylenediamine (en)
H2NCH2CH2NH2
C2H6N2
naming coordination compounds
- cation first
- ligands before metal
- if complex ion is anion, add “ate” to metal
- oxidation state is written in roman numerals
- alphabetical order of ligands
naming ligands in coordination compounds;
H2O
NH3
CO
H2O = aqua
NH3 = ammine
CO - carbonyl
naming ligands in coordination compounds;
anion
Cl =
OH=
CN=
Cl = chloro
OH - hydroxo
CN = cyano
end in “o”
naming ligands in coordination compounds;
ide =
ate =
ite =
ide = o
ate = ato
ite = ito
prefixes for # ligands
2,3,4…
2 = di
3 = tri
4 = tetra
prefixes for polydentate ligands 2,3,4
2 - bis
3 - tris
4 - tetra
name the folllowing
K4[Ni(CN)4]
K2[Cr(H2O)2(C2O4)2]
[Fe(H2O)5OH]Cl2
potassium tetracyanonickelate(0)
potassium diaquabisoxylatochromate(II)
pentaaquahydroxoiron(III) chloride
what is the formula
tris(en)cobalt(III) sulfate
[Co(en)3]2(SO4)3
isomers
compounds with the same number and type of atom but are structurally different
structural and stereoisomers
structural isomers
different bonds
different formula
different name
[MASB]C
[MASC]B
difference in linkage
stereoisomers
same bonds, different orientation
same formula
different name
geometric stereoisomers
cis and trans isomers
cis = AA
BB
trans = AB
BA
optical stereoisomers
one molecule is mirror image
cannot superimpose
which one of the following complexes can have geometric isomers?
A. [Pt(NH3)2Cl2] = square planar
B. [Zn(NH3)2Cl2] = tetrahedral
C. [Cu(NH3)4]2+ = square planar
D. [Cu(NH3)5Cl]2+ = octahedral
E. All
A. [Pt(NH3)2Cl2] = square planar
tetrahedrals can’t have geometric isomers since their geomtry isn’t flat (not on same plane)
square planar C has 4 of the same ligands –> can’t make cis/trans
octahedral has 5 same ligands and 1 Cl –> ca’t make cis/trans
crystal field theory
consider d-orbital orientations and covalent bonds to transition metals
eg = e- density on axis –> dx^2-y^2 and dz^2
t2g = e- density between axes –> dxy dxz dyz
caused by e-/e- repulsions between e- in d-orbitals and e- in covalent bonds
d- orbital diagram for octahedrals
6 covalent bonds
90 degrees
ligaments bond ON axis
^
| _____ _____ eg
| _______ ______ _____t2g
d-orbital diagram for tetrahedral
4 covalent bonds
109.5 degrees
ligands bond between axis
- __ ____ ____ t2g
- ___ ____ eg
______ _____ ______ t2g
d-orbital diagram for square planars
bonds lie on axis
* _____ dx^2-y^2
* ___ dxy
* ___dz^2
* ___ dxz ___ dyz
___ dx^2 - y^2
look over the shapes of each of the d-orbital levels
splitting energy
2 competing effects
1. energy costs from pairing
2. energy costs from promotion
when the splitting energy is small… electrons would rather be promoted(unpaired electrons) (high spin)
when the splitting energy is large – electrons would rather be paired (low spin)
list the general splitting energies for
tetrahedral
square planar
octahedral
tetrahedral = small splitting energy
square planar = large splitting energy
octahedral = look at spectrochemical series
large splitting energy =
paired electrons
small splitting energy
unpaired electrons
rather be promoted
color emission of compounds
result of e- transition between eg and t2g
electrons can absorb photon for promotion
we see reflected light (opposite of color wheel)
calculate energy and wavelength using what equation
E=hc/wavelength
h = 6.626x10^-34 J*s
E = Joules per photon
