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GENERAL CHEMISTRYCHEM-110
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STEREOCHEMISTRY
Same molecular formulas but different connectivity.
STRUCTURAL ISOMERS
CCl2 CH2 CHCl CHCl1,1-dichloroethene 1,2-dichloroethene
C2H2Cl2
Same molecular formulas but different connectivity.
STRUCTURAL ISOMERS
STEREOISOMERS
Same molecular formulas and same connectivity but different orientation in space.
What is the relation between these two What is the relation between these two compounds?compounds?
C CHH
Cl ClC C
Cl
Cl
H
H
1.1. IdenticalIdentical
Iden
tical
Con
stitut
ional is
omer
s
Ster
eoiso
mers
Stru
ctur
al iso
mer
s
0% 0%0%0%
2.2. Constitutional isomersConstitutional isomers
3.3. StereoisomersStereoisomers
4.4. Structural isomersStructural isomers
STEREOISOMERSCHCl CHCl
1,2-dichloroethene
C CHH
Cl ClC C
Cl
Cl
H
H
cis-1,2-dichloroethene trans-1,2-dichloroethene
STEREOISOMERS
CONFORMERS: stereoisomers resulting from free rotation (or a flip) around carbon-carbon bonds.
ENANTIOMERS: stereoisomers that are non
DIASTEREOMERS: stereoisomers that do not result from free rotation and are not mirror image of another.
ENANTIOMERS: stereoisomers that are non-superimposable mirror image of one another.
2
ETHANE
STAGGERED
ECLIPSED ECLIPSED
3
STAGGERED
Newman Projection
STAGGERED ECLIPSED
4
STEREOISOMERS
CONFORMERS: stereoisomers resulting from free rotation (or a flip) around carbon-carbon bonds.
ENANTIOMERS: stereoisomers that are non
DIASTEREOMERS: stereoisomers that do not result from free rotation and are not mirror image of another.
ENANTIOMERS: stereoisomers that are non-superimposable mirror image of one another.
These two molecules have differentconfigurations
They are called enantiomers from the Greek enantio or opposite.
They are also called chiral
STEROISOMERS
ENANTIOMERS: NON-SUPERIMPOSABLE MIRROR IMAGES
STEREOISOMERS
CONFORMERS: stereoisomers resulting from free rotation (or a flip) around carbon-carbon bonds.
ENANTIOMERS: stereoisomers that are non
DIASTEREOMERS: stereoisomers that do not result from free rotation and are not mirror image of another.
ENANTIOMERS: stereoisomers that are non-superimposable mirror image of one another.
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STEREOISOMERS
DIASTEREOMERS
C CHH
Cl ClC C
Cl
Cl
H
H
cis-1,2-dichloroethene trans-1,2-dichloroethene
What is the relation between these two What is the relation between these two compounds?compounds?
C
CH3
HCl
ClC
CH3
HCl
Cl
1.1. IdenticalIdentical
Iden
tical
0% 0% 0%0%0%
2.2. Constitutional isomersConstitutional isomers
3.3. ConformersConformers
4.4. DiastereomersDiastereomers
5.5. EnantiomersEnantiomers5
What is the relation between these two What is the relation between these two compounds?compounds?
C
CH3
HBr Cl
C
CH3
HBrCl
1.1. IdenticalIdentical
Iden
tical
Con
stitut
ional is
omer
s
Con
form
ers
Dias
tereo
mer
s
Ena
ntiom
ers
0% 0% 0%0%0%
2.2. Constitutional isomersConstitutional isomers
3.3. ConformersConformers
4.4. DiastereomersDiastereomers
5.5. EnantiomersEnantiomers5
What is the relation between these two What is the relation between these two compounds?compounds?
CH3
CH3
CH3
CH3
1.1. IdenticalIdentical
Iden
tical
Con
stitut
ional is
omer
s
Con
form
ers
Dias
tereo
mer
s
Ena
ntiom
ers
0% 0% 0%0%0%
:05
2.2. Constitutional isomersConstitutional isomers
3.3. ConformersConformers
4.4. DiastereomersDiastereomers
5.5. EnantiomersEnantiomers
O
CCH2CH3
Carvone
O O
C
CH2CH3
C
H2C CH3
6
d-carvonel-carvone
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DEXFENFLURAMINE LEVFENFLURAMINEDrowsiness
DEXFENFLURAMINE
8
1996Wyeth-Ayerst
DRY MOUTH
DIARRHEA
FATIGUE
PRIMARY PULMONARY HYPERTENSION
FALL 1997
RULES1. Assign priority to the 4 groups attached.
This is based on atomic NUMBER of the atom.
2 Visualize the molecule with the2. Visualize the molecule with the LOWEST priority group AWAY from you.
3. Trace Clockwise orCounterclockwise.
R
RECTUS = RIGHT
S
SINISTER = LEFT
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R/S
The absolute configuration for the structure The absolute configuration for the structure below isbelow is
R S
Neit
her
0% 0%0%
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1. R
2. S
3. Neither
Rules1. Assign priority to the 4 groups attached.
This is based on atomic NUMBER of the atom.
2 Visualize the molecule with the2. Visualize the molecule with the LOWEST priority group AWAY from you.
Double or triple bonds are evaluated as – C holding 2, 3 carbons (Solomons p 192)
C C
H H
H
C C
H H
C
HC
Double or triple bonds are evaluated as – C holding 2, 3 carbons (Solomons p 205)
H HC
C
H
O C
H
O
O C
Same for other species
The absolute configuration for the structure The absolute configuration for the structure below isbelow is
C
CH3
H
CH CH2Cl
R S
0%0%
5
1. R
2. S
10
The absolute configuration for the carvone The absolute configuration for the carvone structure belowstructure below O
CH
R S
0%0%
5
CH3 CH21. R2. S
What relationship exists in the following pair?What relationship exists in the following pair?
H
CH3
H
CH3 H
CH3
H
CH3
Iden
tical
Ena
ntiom
ers
Dias
tereo
mers
0% 0%0%
5
1. Identical
2. Enantiomers
3. Diastereomers
RADIATIONThe transfer of energy throughThe transfer of energy through waves or particles.
Energy
Gamma X rays Ultraviolet rays
Infrared microwave Radio wavesrays
λ
400 nm 600 nm500 nm 700 nm
Hand of Frau Röentgen
November 8, 1895
11
RADIOACTIVITYCan fluorescent materials produce X-rays ?
Antoine HenriBecquerel
1896
The spontaneous emission f di t d
RADIOACTIVITY
of radiant energy, and or, particles from the nucleus of the atom.
Nobel Prize for Physics1903
Ernest Rutherford1899
12
β particles -1 charge
α particles +2 charge
β particles -1 charge
γ radiation
α particlespaper
aluminiumβ particles
leadγ rays
β-
α He24
Nuclei
Electrons: -1e0
γ Electromagnetic radiation
He3 2+
2 protons2 neutrons
2 protons1 neutrons
He4 2+ He2
ISOTOPES
He2
αHe2+ nuclei
24
?Rn86
222He
24
+
13
Which nucleus is produced from the alpha Which nucleus is produced from the alpha decay of radondecay of radon--222?222?
?Rn
86
222He
2
4+
Which nucleus is produced from the Which nucleus is produced from the alpha decay of Radonalpha decay of Radon--222?222?
1.1. RadiumRadium--2262262.2. PoloniumPolonium--22222233 P l iP l i 218218
Rad
ium-226
Polonium-222
Polonium-218
Lead-22
2
None o
f the l
isted
nuclei
0% 0% 0%0%0%
:05
3.3. PoloniumPolonium--2182184.4. LeadLead--2222225.5. None of the listed None of the listed
nucleinuclei
αHe2+ nuclei
24
Rn86
222He
24
+ Po84
218
Half-Life
Time required for half of the number of nuclides to decay
Rn86
222He
24
+ Po84
218
Half-Life = 4 days
NUCLEAR REACTORSSpent FuelPu-239
The halfThe half--life of plutonium is life of plutonium is
1.1. 241 years241 years2.2. 2,410 years2,410 years
241 y
ears
2,41
0 yea
rs
24,10
0 yea
rs
241,0
00 ye
ars
2,41
0,000
years
0% 0% 0%0%0%
:05
3.3. 24,100 years24,100 years4.4. 241,000 years241,000 years5.5. 2,410,000 years2,410,000 years
14
0 50 g
1.0 g
10 Half-Life = 241,000 years
24,100 48,200 72,300 96,400 120,500
0.50 g
0.25 g
0.125 g
40,000 Warheads
150,000 kg of plutonium
Critical mass5kg
If 1.0 grams of plutonium are present If 1.0 grams of plutonium are present initially how much approximately will be left initially how much approximately will be left after 241,000 years?after 241,000 years?
1.1. 100 mg100 mg2.2. 10 mg10 mg
100 m
g
10 m
g 1
mg
0.1 m
g
0.01
mg
0% 0% 0%0%0%
:05
3.3. 1 mg1 mg4.4. 0.1 mg0.1 mg5.5. 0.01 mg0.01 mg
226Ra 218Po
238U
222Rn 214Po
234Th 234U 230Th
Ra Po Rn Po206Pb 210Po
Uranium-238 naturalradioactive decay series
RADIUM WATCHESRadioluminescence
The Radium GirlsOttawa (Illinois)
1920's33 DEATHS
Ra226
Rn222
88 84 He42+
15
226Ra 218Po
238U
222Rn 214Po
234Th 234U 230Th
*Ra PoRn Po206Pb210Po
* gas
16
226Ra 218Po
238U
222Rn 214Po
234Th 234U 230Th
*Ra Po Rn Po206Pb 210Po
Polonium-210
Alexander Litvinenko
Irene Joliot-Curie1897-1956
β-
α He24
Nuclei
Electrons: -1e0
γ Electromagnetic radiation
β-
e- particles
1n β- + p10
1 0-1
Which nucleus is produced from the beta Which nucleus is produced from the beta decay of iodinedecay of iodine--131?131?
I53
132β- ?+
0-1
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Which nucleus is produced from the Which nucleus is produced from the beta decay of Iodinebeta decay of Iodine--131?131?
1.1. TelliriumTellirium--1311312.2. CesiumCesium--13113133 XX 131131
Telliriu
m-131
Ces
ium-131
Xenon-1
31
Telliriu
m-127
None o
f the l
isted
nuclei
0% 0% 0%0%0%
:05
3.3. XenonXenon--1311314.4. TelliriumTellirium--1271275.5. None of the listed None of the listed
nucleinuclei
β-
e- particles
β- Xe131+I131 01β Xe5453
1n β- + p10
1 0-1
-1
Iodine 127
Goiter
Iodine-127
The “goiter belt” was associated with The “goiter belt” was associated with which part of the U.S.?which part of the U.S.?
1.1. The Atlantic coastThe Atlantic coast2.2. The MidwestThe Midwest33 Th S th U STh S th U S
The Atla
ntic co
ast
The Midwes
t
The South
ern U
.S.
The Cali
fornia
coas
t
The South
west
0% 0% 0%0%0%
:05
3.3. The Southern U.S.The Southern U.S.4.4. The California coastThe California coast5.5. The Southwest The Southwest
IODINE-131
18
April 26,1986
IODINE-131IODINE-131
Half-Life 8 Days
IODINE-127Hyperthyroidism
IODINE-131
β- He3 H3+0
1β He21 -1
Tritium Watches
19
β- He3 H3
Half-Life = 12.3 years
+01β He21 +-1
Polonium-210
Po210
Pb206
84 82 He42+
Bi + n Bi210
Po210
+ β-209
83 83 84
RADIATION EXPOSURE
Natural Sources 82%
Medical X-rays 11%Medical X rays 11%
Nuclear Medicine 4%
Consumer Products 3%
Electroluminescence
β-
α He24
Nuclei
Electrons: -1e0
γ Electromagnetic radiation
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γ
High energy electromagneticradiations associated withradiations associated with
nuclear changes Tc43
90m+ γTc90
Half-Life 6 Hours
43 + γTc43
NUCLEAR IMAGING
TECHNETIUM(1937)
Τεχνητόςχ η ς
"Artificial"
β-
α He24
Nuclei
Electrons: -1e0
γ
Positron emission: +1eβ+
Electromagnetic radiation
0
Electron capture
β-
α He24
Nuclei
Electrons: -1e0
γ
Positron emission: +1eβ+
Electromagnetic radiation
0
21
e+ particles
np β+ + 111
0
β+ positron emission
0+1
β+ B5
11+C6
11
p β1 0
0+1
+1
PE TScan
6C6H12O6
Glucose
11Normal Depressed
Frontal lobe
Normal Criminal
22
β-
α He24
Nuclei
Electrons: -1e0
γ
Positron emission: +1eβ+
Electromagnetic radiation
0
Electron capture
Electron capture
np -1e+ 111
00
Rb8137 ++ -1e
0 Kr8136
α
Num
ber o
f Neu
trons
Number of Protons
β+(or electron capture)
β-
NATURALRADIOACTIVITY
Ernest Rutherford
1871-1937
N + He O + H
TRANSMUTATION(1919)
414 1177N + 2He O + 1H8
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ARTIFICIAL RADIOACTIVITY
Irene and Frederic Joliot-Curie
13Al + 2He 15P + 0n427 30 1
30 30 015P 14Si + +1β30 30 0
NATURALRADIOACTIVITY
How Fast?
Rate of Decay = Activity A
A = k x N
A Number of disintegrations per
k decay constant
N Number of nuclei presentat a given time
unit time
Ln(N0/2No
) = -k x t1/2
No/2 Number of nuclei present at time t1/2
t1/2 Half-Life
Ln( 1/21 ) = -k x t1/2
k x t1/2 = 0.693
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Ln( NNo
) = -k x t
k = 0.693 / t1/2
CARBON 14 DATINGCARBON-14 DATING
12C 13C 14C*12C 13C 14C* β-N14 C14 + 0 βN7C
6+
-1
Half-life = 5730 YEARS
β-N14 C14 + 0
HC614N
714 + 1
1
Atmosphere
βN7C
6+
-1
Carbon Cycle
14C/12C Constant
25
Carbon Cycle14C/12C decreases
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.
Ln( NNo
) = -k x t
k = 0.693 / 5730 yr -1
Ln( NNo
) = -k x t
k = 1.21 x 10 -4 yr -1
Ln(11.715.3
) = -1.21 x 10 -4 x t
t = 2,200 years
CarbonCarbon--14 dating can be used for samples as 14 dating can be used for samples as old as?old as?
1. 500 years
2. 1,000 years
500 y
ears
1,00
0 yea
rs
10,00
0 yea
rs
50,00
0 yea
rs
100,0
00 ye
ars
0% 0% 0%0%0%
:05
3. 10,000 years
4. 50,000 years
5. 100,000 years
26
The term The term sindonologysindonology applies to the study of?applies to the study of?
1. the Shroud of Turin.
2. old paintings.
the S
hroud
of Turin
.
old pain
tings.
the a
ge of th
e eart
h.
the c
ause
of N
apoleo
n..
the a
ge of a
pes.
0% 0% 0%0%0%
:05
3. the age of the earth.
4. the cause of Napoleon’s death.
5. the age of apes.THE SHROUD OF TURIN
CARBON-14 DATINGDECAY MEASUREMENT
CARBON-14 DATINGDECAY MEASUREMENT
ISOTOPE COUNTS (MACS)
1260-1390 October 5, 2009