3. Chapter 1 3
SHORT HISTORY OF
CHEMISTRY
PRE-1828 ERA
TWO MAJOR DISCIPLINES EMERGING
INORGANIC - MINERAL CHEMISTRY
ORGANIC CHEMISTRY - PLANTS AND ANIMALS
4. Chapter 1 4
FIRE AGE - BASED ON COMBUSTION
COMBUSTIBLES - FUELS FROM ANIMALS AND PLANTS
OIL, WOOD, FAT
NON-COMBUSTIBLES -DIDNÕT BURN; PUT OUT FIRES
SAND, WATER, ROCKS
CLASSIFICATION OF MATTER
Classification of Matter
5. Chapter 1 5
ORGANIC COMPOUNDS
CHARACTERISTIC PRODUCTS OF LIVING ORGANISMS
SUBSTANCES LIKE SUGAR AND OLIVE OIL
INORGANIC COMPOUNDS
PRODUCTS FROM NON-LIVING ENVIRONMENT
SUBSTANCES LIKE WATER AND IRON
BERZILIUS’ DEFINITIONS
6. Chapter 1 6
Vital Force Theory
INORGANIC MATERIALS COULD BE CONVERTED
TO ORGANIC MATERIALS IN THE PRESENCE OF A
VITAL FORCE FOUND ONLY IN LIVING BODIES.
7. Chapter 1 7
In addition to Vital Force Theory
Organics hard to purify
Appeared to violate the Law of Definite Proportions
Organic Little Studied
Isomerism problem - same molecular formula but
Different compounds
Consider ethanol and dimethyl ether
8. Chapter 1 8
Woehler’s urea synthesis
Ammonium isocyanate + heat ------> urea
NH4CNO
NH2CONH2
“I have been able to make urea without aid of kidney
of man or dog.
1828
1828
15. Chapter 1 15
BIRTHS
JULES VERNE - AROUND THE WORLD IN 80 DAYS
LEO TOLSTOY - ANNA KORNINA, KREUTZER SONATA
HANS CHRISTIAN ANDERSON
WANG TAO - CHINESE SELF-STRENGTHENING
MOVEMENT
AMEER MINAI - INDIAN SONG WRITER - AAHISTAA
MARRIAGES
BARTHOLOMEW HEIFNER AND POLLY GRISHAM.
IN SHELBY COUNTY, ENGLAND
16. Chapter 1 16
Wang Tao
Attempted to bring China into the 19th Century
Was put to death
17. Chapter 1 17
IMPORTANT EVENTS
ANDREW JACKSON ELECTED PRESIDENT OF USA
DEFEATED JOHN Q. ADAMS
RUSSO-PERSIAN WAR ENDED
FATH ‘ALI SHAH’ AND RUSSIAN COUNTERPART
SIGNED TURKMANCHAI TREATY
GAVE RUSSIA - GEORGIA, ARMENIA, AND AZERBAIJAN
18. Chapter 1 18
Post 1828
•Over 18,000 million compounds have been synthesized
•Pharmaceuticals
•Biochemicals
•Plastics
•Agrichemicals
•Paints
19. Chapter 1 19
Why so many organic?
H O N X P S Se
FORMS COVALENT BONDS WITH MANY METALS
Li Mg Al Cd Fe
FORMS COVALENT BONDS WITH NON-METALS
23. Chapter 1 23
Electronic Configurations
• Aufbau principle:
Place electrons in
lowest energy
orbital first.
• Hund’s rule:
Equal energy
orbitals are half-
filled, then filled.
↑↓
↑↓
↑
=>
↑
25. Chapter 1 25
Bond Formation
• Ionic bonding: electrons are transferred.
• Covalent bonding: electron pair is shared.
=>
26. Chapter 1 26
Lewis Structures
• Bonding electrons
• Nonbonding electrons or lone pairs
Satisfy the octet rule! =>
C
H
H
H
O
H
27. Chapter 1 27
TIPS
• Neutral atoms
Carbon 4 bonds (double bonds count as 2
triple bonds count as 3) and NO lone pairs.
Nitrogen 3 bonds and one lone pair
Oxygen 2 bonds and two lone pairs
BORON 3 bonds BUT no lone pairs
One who writes MORE than 3 bonds about a
neutral BORON is a MORON
28. Chapter 1 28
C H
-H+
C
H- -
C
+
N H
-H+
N
+H+
N HH
+
O
H
-H+
O+H+
O
H
+
H
TIPS2
31. Chapter 1 31
Dipole Moment
• Amount of electrical charge x bond length.
• Charge separation shown by electrostatic potential
map (EPM).
• Red indicates a partially negative region and blue
indicates a partially positive region.
C C
H
H H
H
=>
34. Chapter 1 34
Calculating Formal Charge
• For each atom in a valid Lewis structure:
• Count the number of valence electrons
• Subtract all its nonbonding electrons
• Subtract half of its bonding electrons
C
H
H
H
C
O
O P
O
OO
O
3-
=>
36. Chapter 1 36
Ionic Structures
C
H
H
H N
H
H
H
+
Cl
-
Na O CH3 or O CH3Na
+
_
X
=>
37. Chapter 1 37
Resonance - More than
one Lewis Diagram
Example=>
C
O
C O
H
H H
-1
Acetate ion
N
O
O
:
38. Chapter 1 38
Resonance Example
• Consider writing Lewis structure for NO3
-2
• The real structure is a resonance hybrid.
• All the bond lengths are the same.
• Each oxygen has a -1/3 electrical charge.
=>
N
O
OO
_ _
N
O
OO
_
N
O
OO
39. Chapter 1 39
Must be legitimate Lewis structures
N
CH3
H3C
CH3
CH2
+
-
N
CH3
H3C
CH3
CH2
NO NO
Pentavalent nitrogen atom!!
Resonance Rules
40. Chapter 1 40
• Only electrons can be moved (usually lone
pairs or pi electrons).
42. Chapter 1 42
Nuclei positions and bond
angles remain the same.
C=C-C+ +C-C=C
CAN”T SAY “if you turn one around 180o
you would
End up with same structure”
Doing so would violate this rule
43. Chapter 1 43
The number of unpaired
electrons remains the same
H3C CH3
.. H3C CH3
. .
NO NO
44. Chapter 1 44
DELOCALIZATION OF
CHARGE USUALLY IS
STABILIZING
Delocalization of charge results in fractional charges
at alternate atoms
45. Chapter 1 45
Major Resonance Form
• has as many octets as possible.
• has as many bonds as possible.
• has the negative charge on the most
electronegative atom.
• has as little charge separation as
possible.
Example=>
46. Chapter 1 46
Major Contributor?
C
H
H
N
H
H
+
C
H
H
N
H
H
+
major minor,
carbon does
not have octet.
=>
48. Chapter 1 48
Chemical Formulas
• Full structural formula
(no lone pairs shown)
• Line-angle formula
• Condensed structural
formula
• Molecular formula
• Empirical formula
CH3COOH
• C2H4O2
• CH2O
=>
C
H
H
H
C
O
O H
OH
O
49. Chapter 1 49
BrØnsted-Lowry
Acids and Bases
• Acids can donate a proton.
• Bases can accept a proton.
• Conjugate acid-base pairs.
CH3 C
O
OH + CH3 NH2 CH3 C
O
O
-
+ CH3 NH3
+
=>
acid base conjugate
base
conjugate
acid
50. Chapter 1 50
CH3CO2H + :NH3 CH3CO2
- + NH4
+
ACID
BASE
CONJ BASE
CONJ ACID
H3C
O:
OH
+ H2SO4
H3C
OH
OH
+
+ -
HSO4
Amphoterism - ability to behave as an acid or base
EXAMPLES
51. Chapter 1 51
Acid and Base Strength
• Acid dissociation constant, Ka
• Base dissociation constant, Kb
• For conjugate pairs, (Ka)(Kb) = Kw
• Spontaneous acid-base reactions
proceed from stronger to weaker.
CH3 C
O
OH + CH3 NH2 CH3 C
O
O
-
+ CH3 NH3
+
pKa 4.74 pKb 3.36 pKb 9.26 pKa 10.64
=>
55. Chapter 1 55
Size
• As size increases, the H is more loosely
held and the bond is easier to break.
• A larger size also stabilizes the anion.
=>
56. Chapter 1 56
Resonance
• Delocalization of the negative charge on the
conjugate base will stabilize the anion, so the
substance is a stronger acid.
• More resonance structures usually mean
greater stabilization.
CH3CH2OH < CH3C
O
OH < CH3 S
O
O
OH
=>
57. Chapter 1 57
Lewis Acids and Bases
• Acids accept electron pairs = electrophile
• Bases donate electron pairs = nucleophile
CH2 CH2 + BF3 BF3 CH2 CH2
+_
nucleophile electrophile
=>
