classes%5CWinter09%5C171ID38%5CFinalExamCHEM171w07

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 CHEM
171,
FINAL
EXAM,
MAR
22
07,
W’07,
YAGHI,
200
points
 NAME:
 
 Signature:
 NOTE:
The
exam
is
15
questions
on
five
pages
onto
which
you
should
provide
your
answers.
 For
questions
1‐10
determine
if
the
statement
is
true
or
false
by
circling
T
or
F.
Provide
the
correct
 answer
for
those
false
cases.
(5
points
each)
 1. T

 
 2. T

 
 3. T

 
 4. T


 
 5. T

 
 6. T

 
 7. T

 
 8. T

 
 9. T

 
 10. T

 or

 F
 All
sulfur
allotropes
have
a
doubly
bridging
S
with
formal
charge
of
zero
 or

 F
 In
Si2O52‐
each
Si
must
have
one
terminal
and
3
bridging
O
atoms
 or

 F
 Addition
of
water
to
and
high
heating
of
SiCl4
should
give
Si(l).

 or

 F
 The
reaction
of
B2H6
with
water
gives
H3BO3
 or

 F In
MgX2O4
each
X
is
bonded
to
6
Oxygen
atoms


 or

 F
 The
geometry
of
around
Pt
in
PtS

is
predictably
tetrahedral

 or

 F
 The
geometry
of
Al
in
Al2O3
is
tetrahedral

 or

 F
 BF3
unit
in
F3B‐NH3
complex
is
planar
 or

 F
 Reaction
of
Li(s)
with
N2
is
most
likely
to
yield
LiN2‐
 or

 F
 Lewis
acid‐Lewis
base
interaction
results
in
lower
energy
of
the
lone
pair
 
 
 
 
 
 
 
 
 TA:
 2
 
 11. (20
points)
Draw
or
describe
the
structures
of
each
of
the
following
compounds
and
determine
 whether
they
are
molecular
or
extended
solids:
 
 a. SiO2
(cristobalite)
 
 
 
 
 
 b. P4O10
 
 
 
 
 
 c. ZnS
(zinc
blend)

 
 
 
 
 
 d. S8
 
 
 
 3
 
 e. (20
points)
For
each
of
the
following
ligands,
draw
an
example
of
a
metal
complex
 containing
at
least
one
of
the
ligand
and
give
the
chemical
formula
:
 f. Oxalate
 
 
 g. 2,2’‐bipyridine
 
 
 h. Acac
 
 
 
 i. 
 
 
 
 12. (30
points)
Determine
whether
each
of
the
following
compounds
has
a
legitimate
formula.
For
 those
that
don’t,
derive
a
legitimate
formula
without
adding
charge
or
new
type
of
atoms.
For
 all,
draw
a
possible
structure.

 a. Hg(CN)2
 
 en
 
 b. B3S4Br3
 
 
 4
 
 c. B(CH3)4
 
 
 
 d. PB4F8
 
 
 
 e. Si8O20(CH3)8
 
 
 
 
 f. 
 
 
 
 
 
 
 
 
 
 
 BN
 5
 
 13. (25
points)
Complete
the
following
reactions:

 a. LiAlH4

 +

 
 b. PtCl2
 
 c. BCl3
 
 d. SO2
 
 e. Li
 
 
 14. (30
points)
Consider
the
compounds
PtF6
and
W(CO)6.
 a. For
each
compound,
draw
a
molecular
orbital
diagram
that
includes
only
the
highest
 occupied
and
lowest
unoccupied
molecular
orbitals
(HOMO
and
LUMO).

Label
your
 diagram
and
fill
the
electrons
appropriately.
 
 
 
 
 
 
 
 
 
 
 +
 C(graphite)
 →
 +



 H2O

 →
 
 
 
 
 +



 (Et)2NH
 →
 +

 2NH3



 →
 ROH
 
→ 
 6
 
 b. Circle
the
MO
diagram
of
the
compound
that
is
most
likely
to
undergo
Jan‐Teller
 distortion.

Draw
a
new
HOMO
and
LUMO
for
that
compound
in
its
distorted
form
(do
 not
label
your
new
diagram).
 
 
 
 
 
 
 
 
 
 
 c. You
react
rutile
(TiO2)
with
chlorine
gas
at
high
temperature.

After
purification,
the
 resulting
compound
is
colorless.

Propose
a
formula
for
the
compound.

Many
transition
 metal
complexes
are
colored.

Explain
the
lack
of
color
observed
in
your
compound
in
 no
more
than
two
sentences.
 
 
 
 
 
 
 
 
 
 7
 
 d. What
was
the
coordination
geometry
of
titanium
before
you
performed
the
reaction?

 What
is
the
coordination
geometry
after
you
perform
the
reaction?
 
 
 
 
 e. Draw
the
structures
of
Pt(NH3)2Cl2
and
Zn(NH3)2Cl2,
clearly
indicating
the
geometry
 around
the
metal
center
in
each
case.
 
 
 
 
 
 
 
 
 
 
 15. (25
points)

 a. What
is
the
total
valence
electron
count
on
the
metal
in
OsO42‐
(show
your
work)
 
 
 
 b. Do
you
think
the
V(CO)6‐1
complex
anion
is
known,
why
or
why
not?
(one
sentence
 answer)
 
 8
 
 
 c. What
is
the
atomic
connectivity
within
a
crystal
of
K4[V(CN)7].2H2O
?
Show
the
geometry
 around
V
and
state
the
kind
of
specific
interactions
holding
the
crystal
together.
 
 
 
 
 
 
 d. What
is
the
structure
of
Fe(N3)52‐?
What
is
the
geometry
around
Fe?
 
 
 
 
 
 e. What
is
the
total
number
of
valence
electrons
around
Fe
in
d?
 ...
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