GENERAL CHEMISTRY
CHEM-110
STRUCTURAL ISOMERS
Same molecular formulas but different
connectivity.
CCl 2 CH2
CHCl CHCl
1,1-dichloroethene
1,2-dichloroethene
C2H2Cl2
STEREOCHEMISTRY
1
What is the relation between these two
compounds?
STRUCTURAL ISOMERS
Same molecular formulas but different
connectivity.
H
H
Cl
C C
Cl
H
C C
Cl
Cl
H
1. Identical
STEREOISOMERS
2. Constitutional isomers
STEREOISOMERS
CHCl CHCl
H
Cl
Cl
H
C C
Cl
Stereoisomers
4. Structural isomers
0%
0%
0%
0%
STEREOISOMERS
CONFORMERS: stereoisomers resulting from
free rotation (or a flip) around carbon-carbon
bonds.
1,2-dichloroethene
H
3.
C
Id
on
en
st
tic
itu
al
tio
na
li
so
m
er
s
St
er
eo
is
om
S
e
tr
rs
uc
tu
ra
li
so
m
er
s
Same molecular formulas and same
connectivity but different orientation in
space.
H
ENANTIOMERS: stereoisomers that are non
nonsuperimposable mirror image of one another.
C C
cis-1,2-dichloroethene
Cl
trans-1,2-dichloroethene
DIASTEREOMERS: stereoisomers that do not
result from free rotation and are not mirror image
of another.
1
ETHANE
STAGGERED
ECLIPSED
ECLIPSED
2
Newman
Projection
STAGGERED
STAGGERED
ECLIPSED
3
STEREOISOMERS
CONFORMERS: stereoisomers resulting from
free rotation (or a flip) around carbon-carbon
bonds.
ENANTIOMERS: stereoisomers that are non
nonsuperimposable mirror image of one another.
DIASTEREOMERS: stereoisomers that do not
result from free rotation and are not mirror image
of another.
These two molecules have different
configurations
They are called enantiomers from the Greek
enantio or opposite.
They are also called chiral
STEREOISOMERS
STEROISOMERS
CONFORMERS: stereoisomers resulting from
free rotation (or a flip) around carbon-carbon
bonds.
ENANTIOMERS: stereoisomers that are non
nonsuperimposable mirror image of one another.
ENANTIOMERS: NON-SUPERIMPOSABLE
MIRROR IMAGES
DIASTEREOMERS: stereoisomers that do not
result from free rotation and are not mirror image
of another.
4
What is the relation between these two
compounds?
STEREOISOMERS
CH3
H
DIASTEREOMERS
CH3
C
Cl
C
Cl
Cl
H
Cl
1. Identical
H
H
Cl
C C
Cl
H
2. Constitutional isomers
C C
Cl
3.
Cl
H
Conformers
4. Diastereomers
What is the relation between these two
compounds?
H
CH3
CH3
C
C
Br
Cl
Cl
Br
0%
H
CH3
CH3
CH3
2. Constitutional isomers
2. Constitutional isomers
0%
0%
0% 0%
C
on
Id
st
en
itu
tic
tio
al
na
li
so
m
er
s
C
on
fo
rm
er
D
ia
s
st
er
eo
m
er
s
E
na
nt
io
m
er
s
4. Diastereomers
0%
5. Enantiomers
3.
Conformers
5
5. Enantiomers
0%
0% 0%
O
C
C
CH3
0%
:0
5
O
C
CH2
0%
4. Diastereomers
O
CH3
0%
5
CH3
1. Identical
Conformers
0%
What is the relation between these two
compounds?
1. Identical
3.
0%
ic
al
5. Enantiomers
0%
Id
en
t
trans-1,2-dichloroethene
C
on
Id
st
en
itu
tic
tio
al
na
li
so
m
er
s
C
on
fo
rm
er
D
ia
s
st
er
eo
m
er
s
E
na
nt
io
m
er
s
cis-1,2-dichloroethene
CH2
H2C
CH3
Carvone
5
d-carvone
l-carvone
6
DEXFENFLURAMINE
LEVFENFLURAMINE
Drowsiness
DEXFENFLURAMINE
7
DRY MOUTH
DIARRHEA
FATIGUE
PRIMARY PULMONARY HYPERTENSION
Wyeth-Ayerst
1996
RULES
1. Assign priority to the 4 groups attached.
This is based on atomic NUMBER of the
atom.
2 Visualize the molecule with the
2.
LOWEST priority group AWAY from
you.
3. Trace Clockwise or
Counterclockwise.
FALL 1997
R
S
RECTUS = RIGHT
SINISTER = LEFT
8
The absolute configuration for the structure
below is
1.
R
2.
S
3. Neither
0%
R
S
0%
0%
N
ei
th
er
R/S
5
Rules
1. Assign priority to the 4 groups attached.
This is based on atomic NUMBER of the
atom.
H
H
H
H
C
C
C
C
H
C
H
2 Visualize the molecule with the
2.
LOWEST priority group AWAY from
you.
Double or triple bonds are evaluated
as – C holding 2, 3 carbons
(Solomons p 192)
O
3
C
O
O
C
Cl
C
CH
CH2
H
1.
R
2.
S
Same for other species
R
0%
0%
S
C
Double or triple bonds are evaluated as – C
holding 2, 3 carbons (Solomons p 205)
The absolute configuration for the structure
below is
CH
H
H
C
5
9
The absolute configuration for the carvone
structure below
O
1.
Identical
2.
Enantiomers
CH3
3. Diastereomers
0%
H
0%
5
0%
0%
5
D
R
0%
H
er
s
CH2
H
ia
st
er
eo
m
er
s
CH3
CH3
CH3
E
na
nt
io
m
R
S
H
Id
en
tic
al
1.
2.
CH3
H
S
C
What relationship exists in the following pair?
Energy
RADIATION
The transfer of energy through
waves or particles.
Gamma
rays
X rays Ultraviolet
Infrared
microwave
Radio waves
λ
Hand of Frau Röentgen
November 8, 1895
400 nm
500 nm
600 nm
700 nm
10
Can fluorescent
materials produce
X-rays ?
RADIOACTIVITY
Antoine Henri
Becquerel
1896
RADIOACTIVITY
The spontaneous emission
off radiant
di t energy, and
d or,
particles from the nucleus
of the atom.
Nobel Prize for Physics
1903
Ernest Rutherford
1899
11
α particles
+2 charge
β particles
-1 charge
γ
α particles
paper
radiation
α
4
2
β particles
β-
aluminium
γ
γ rays
2 protons
2 neutrons
4
2+
He
2
He
Nuclei
0
-1e
Electrons:
Electromagnetic radiation
lead
2 protons
1 neutrons
3
2+
He
2
4
He2+
2
222
86
Rn
α
nuclei
4
2
He
+ ?
ISOTOPES
12
Which nucleus is produced from the alpha
decay of radonradon-222?
2
He
+
?
1.
2.
3
3.
4.
5.
Radium
Radium--226
Polonium
Polonium--222
P l i -218
PoloniumPolonium
Lead--222
Lead
None of the listed
nuclei
0% 0% 0% 0% 0%
Po
R
86
ad
iu
m
-2
26
iu
m
-2
Po
22
lo
ni
um
-2
18
N
on
Le
e
of
ad
th
-2
e
22
li s
te
d
nu
cl
ei
4
lo
n
222 Rn
Which nucleus is produced from the
alpha decay of RadonRadon-222?
:05
Half-Life
α
4 He2+ nuclei
2
222
86
Rn
4
2
He
Time required for half of the number
of nuclides to decay
+
218
84
Po
222
86
Rn
4
2
He
218
+
84
Po
Half-Life = 4 days
The half
half--life of plutonium is
0%
41
0,
00
0
ye
ar
s
0%
2,
24
,
10
0
ye
ar
s
0%
ye
ar
s
ye
ar
s
0%
24
1,
00
0
24
1
ye
ar
s
0%
2,
41
0
NUCLEAR REACTORS
Spent Fuel
Pu-239
1. 241 years
2. 2,410 years
3. 24,100 years
4. 241,000 years
5. 2,410,000 years
:05
13
1.0 g
40,000 Warheads
10 Half-Life = 241,000 years
150,000 kg of
plutonium
0 50 g
0.50
Critical mass
5kg
0.25 g
0.125 g
24,100
48,200
72,300
96,400
120,500
If 1.0 grams of plutonium are present
initially how much approximately will be left
after 241,000 years?
100 mg
10 mg
1 mg
0.1 mg
0.01 mg
234Th
226Ra
m
g
0%
01
:05
230Th
218Po
214Po
206Pb
Uranium-238 natural
radioactive decay series
0.
1
0.
m
g
1
0%
m
g
0%
m
g
0%
10
m
g
0%
234U
222Rn
210Po
10
0
1.
2.
3.
4.
5.
238U
The Radium Girls
Ottawa (Illinois)
1920's
33 DEATHS
RADIUM WATCHES
Radioluminescence
226
88 Ra
222
84
Rn +
4
2
He
14
238U
234Th
226Ra
210Po
234U
*
222Rn
218Po
230Th
214Po
206Pb
* gas
15
Polonium-210
238U
234Th
234U
*
226Ra
222Rn
210Po
230Th
218Po
214Po
206Pb
Alexander Litvinenko
α
4
2
β-
He
Nuclei
Electrons:
γ
0
-1e
Electromagnetic radiation
Irene Joliot-Curie
1897-1956
Which nucleus is produced from the beta
decay of iodineiodine-131?
β-
132
e- particles
1n
0
0 β
-1
53
+
1
1
I
0 β
-1
+
?
p
16
Which nucleus is produced from the
beta decay of IodineIodine-131?
e- particles
Tellirium
Tellirium--131
CesiumCesium-131
X
XenonXenon
-131
Tellirium
Tellirium--127
None of the listed
nuclei
131
I
53
0% 0% 0% 0% 0%
lli
r iu
m
-1
31
es
iu
m
-1
31
Xe
no
n13
N
Te
1
on
l
l
ir i
e
of
um
th
12
e
li s
7
te
d
nu
cl
ei
1n
0
0 1β
-1
131
+
0 β
-1
54
1
+
1
C
Te
Xe
p
:05
The “goiter belt” was associated with
which part of the U.S.?
0%
ut
h
w
es
t
.
U.
S
co
Th
e
So
ia
er
n
rn
ut
h
So
al
i fo
C
e
0%
as
t
0%
e
co
a
ic
M
e
Th
tla
nt
A
e
Goiter
0%
id
w
es
t
st
0%
Th
The Atlantic coast
The Midwest
Th Southern
The
S th
U
U.S.
S
The California coast
The Southwest
Th
Iodine 127
Iodine-127
1.
2.
3
3.
4.
5.
Th
1.
2.
3
3.
4.
5.
β-
:05
IODINE-131
17
April 26,1986
3
H
1
IODINE-131
IODINE-131
Half-Life 8 Days
IODINE-127
Hyperthyroidism
IODINE-131
0 -1
1β
+
3
2
He
Tritium Watches
18
Half-Life = 12.3 years
3
0 -1
1β
H
1
+
3
2
Polonium-210
He
210
84 Po
206
82 Pb
+
4
2
He
RADIATION EXPOSURE
209
83
Bi + n
210
83
Bi
210
84
Natural Sources
82%
Medical X-rays
X rays
11%
Nuclear Medicine
4%
Consumer Products
3%
Po + β-
α
4
2
βγ
He
Nuclei
Electrons:
0
-1e
Electromagnetic radiation
Electroluminescence
19
γ
Half-Life 6 Hours
High energy electromagnetic
radiations associated with
nuclear changes
90m
Tc
43
90
Tc
43
+
γ
NUCLEAR IMAGING
TECHNETIUM
(1937)
Τεχνητός
χ η ς
"Artificial"
α
4
2
β-
He
α
Nuclei
Electrons:
4
2
β-
0
-1e
γ
Electromagnetic radiation
β+
Positron emission:
0
+1e
He
Nuclei
Electrons:
0
-1e
γ
Electromagnetic radiation
β+
Positron emission:
0
+1e
Electron capture
20
β+ positron emission
e+ particles
1p
1
11
6
C
0 +
+1β
+
0 +
β
+1
+
1
n
0
11
5
B
PE T
Scan
11
6C6H12O6
Normal
Depressed
Glucose
Frontal lobe
Normal
Criminal
21
α
4
2
βγ
β+
He
Electron capture
Nuclei
Electrons:
1
0
-1e
1
p
0
+
-1e
1
n
0
Electromagnetic radiation
Positron emission:
81
Rb
37
0
+1e
+
0
-1e
81
Kr
36
Electron capture
NATURAL
RADIOACTIVITY
Number of Neutrons
α
β-
β+
(or electron capture)
Number of Protons
TRANSMUTATION
(1919)
14
4
7N + 2He
17
1
8 O + 1H
Ernest Rutherford
1871-1937
22
ARTIFICIAL RADIOACTIVITY
27
13Al
+ 42He
30
15P
30
15P
30
14Si
+
1
+ 0n
0
+1β
Irene and Frederic Joliot-Curie
Rate of Decay = Activity A
NATURAL
RADIOACTIVITY
How Fast?
A=kxN
A
k
N
Ln(
N0/2
) = -k x t1/2
No
No/2
Number of nuclei
present at time t1/2
t1/2
Half-Life
Number of disintegrations per
unit time
decay constant
Number of nuclei present
at a given time
Ln(
1/2
1
)=
-k x t1/2
k x t1/2 = 0.693
23
Ln(
N
No
)=
-k x t
CARBON 14 DATING
CARBON-14
k = 0.693 / t1/2
12C
13C
14C*
14
14
C
7
6
N
+ -10 β-
Half-life = 5730 YEARS
Atmosphere
14
N
7
14
C
6
14
C
+ 11 H
N
+ -10 β-
6
14
7
14C/12C
Constant
Carbon Cycle
24
Example
An ancient wooden shovel has an activity
of 11.6 dis x min-1 x g-1.
Given that the activity of carbon-14 in
equilibrium with the environment is 15.3
dis x min-1 x g-1 calculate the age of the
object.
14C/12C
decreases
Carbon Cycle
Ln(
-k x t
k = 0.693 / 5730 yr -1
-1.21 x 10 -4
)=
-k x t
k = 1.21 x 10 -4 yr -1
x
t
Carbon-14 dating can be used for samples as
Carbonold as?
1. 500 years
2. 1,000 years
3. 10,000 years
4. 50,000 years
0%
10
0,
00
0
ye
ar
ye
ar
0%
ye
ar
s
s
0%
s
0%
50
,0
00
0%
5. 100,000 years
ye
ar
s
t = 2,200 years
10
,0
00
15.3
)=
No
ye
ar
s
Ln(
11.7
N
00
0
No
)=
1,
N
50
0
Ln(
:05
25
The term sindonology applies to the study of?
1.
the Shroud of Turin.
2. old paintings.
3. the age of the earth.
DECAY MEASUREMENT
..
es
.
ap
le
on
of
ag
e
e
ap
o
e
th
CARBON-14 DATING
th
s.
th
e
of
of
N
ag
e
ca
us
e
ur
in
.
tin
g
of
T
pa
in
d
e
th
ro
ud
Sh
th
e
ol
5. the age of apes.
ea
rt
h.
0% 0% 0% 0% 0%
4. the cause of Napoleon’s death.
:05
THE SHROUD OF TURIN
CARBON-14 DATING
DECAY MEASUREMENT
ISOTOPE COUNTS (MACS)
1260-1390
October 5, 2009
26