Organic Chemistry PART 1

Organic Chemistry

→ A branch of chemistry that studies carbon-containing compounds

Organic Compounds

→ Compounds that contain carbon

→ Except: Carbonates, cyanides, and oxides of carbon (CO2, CO) → inorgranic compounds

Jöns Jacob Berzelius

Proposed the Vital Force Theory (Life Force Theory) → "Organic compounds are only derived from living things."

Friedrich Wöhler

Disproved the Vital Force Theory by synthesizing urea from inorganic precursors. (Ammonium Cyanate)

Common Elements in Organic Compounds

Carbon (C)

Hydrogen (H)

Oxygen (O)

Nitrogen (N)

Carbon (C)

Mass Number: 12

Atomic Number/Proton: 6

Neutron: 6

Electron: 6

Electron Configuration: 1s²2s²2p²

Valence: 4

Binding Sites: 4 - it only shares

Hydrogen (H)

Mass Number: 14

Atomic Number/Proton: 7

Neutron: 7

Electron: 7

Electron Configuration: 1s²2s²2p³

Valence: 5

Binding Sites: 3

Oxygen (O)

Mass Number: 16

Atomic Number/Proton: 8

Neutron: 8

Electron: 8

Electron Configuration: 1s²2s²2p⁴

Valence: 6

Binding Sites: 2

Nitrogen (N)

Mass Number: 1

Atomic Number/Proton: 1

Neutron: 0

Electron: 1

Electron Configuration: 1s¹

Valence: 1

Binding Sites: 1

Stability of Carbon

→ Requires 4 bonds to become stable

→ Octet Rule: Atoms prefer 8 electrons in their valence shell

Catenation

→ Ability of carbon to bond with itself to form chains and rings

1. High carbon-carbon C-C bond energy

2. Tetravalency - large # of bonds

3. Small atomic size

Hybridization

Atomic orbitals fuse to form new hybrid orbitals

• Atomic orbitals - these are region in space in which electrons are most likely to be found.

Sublevel s

Meaning: Sharp

Shape: Sphere

# of Orbitals : 1

# of Electrons: 2

Sublevel p

Meaning: Principal

Shape: Dumbbell

# of Orbitals : 3

# of Electrons: 6

Sublevel d

Meaning: Diffuse

Shape: Four-leaf clover

# of Orbitals : 5

# of Electrons: 10

Sublevel f

Meaning: Fundamental

Shape: Complex

# of Orbitals: 7

# of Electrons: 14

Hybrid Orbitals

orbitals of equal energy produced by the combination of two or more orbitals on the same atom

Sigma bond (σ)

First bond, hybridized orbital

Pi bond (π)

Second/third bond, unhybridized orbital

sp³

Sigma bond (σ): 4

Pi bond (π): 0

sp²

Sigma bond (σ): 3

Pi bond (π): 1

sp¹

Sigma bond (σ): 2

Pi bond (π): 2

Methane CH4

• Carbon bonded to 4 hydrogen atoms

• Bond between H and C is called SIGMA BOND

• Meaning 4 sigma bonds have formed - so the hybridization is sp³

Formaldehyde

• 2 single bonds and 1 double bond

• 3 sigma bond and 1 pi bond

• So the hybridization is sp²

HCN

• There is 1 single bond and 1 triple bond

• So there is 2 sigma bonds and 2 pi bonds

• The hybridization is sp

CO2

• There is 2 double bonds O=C=O

• 2 sigma bonds, and 2 pi bonds

• The hybridization is sp

true

Group #

1 - s

2 - sp

3 - sp²

4 - sp³

• check how many groups are attached to carbon to easily determine the hybridization

Ethane

• Attached to the first carbon is: 4 sigma bonds - so it's sp³

• Attached also to the second carbon is: 4 sigma bonds - so it's also sp³

Ethene

• Attached to the 1st carbon is: 3 sigma bonds and 1 pi bond

• Attched to the 2nd carbon is: 3 sigma bonds and 1 pi bond also

• The hybridization is sp²

Ethyne

• Attched to the 1st carbon is: 2 sigma bonds and 1 pi bond

• Attched to the 2nd carbon is: 2 sigma bonds and 2 pi bonds

• The hybridization is sp

true

Different structural formula of a molecule with the molecular formula, C3H8 - PROPANE

true

Draw the Kekule Structure of the following

1. CH₃CH₂CH₂CH₃

2. CH₃CHCH₂

3. CH₃CH₂COOH

4. CH₃CH₂COCH₂COOH

C. sp³ - sp³

What are the hybridizations of the orbitals between carbons 3 and 4 in the molecule CH₂=CHCH₂CH₂CH₃?

A. sp² - sp³

B. sp² - sp²

C. sp³ - sp³

D. sp - sp²

B. sp² - sp²

What are the hybridizations of the orbitals between carbons 1 and 2 in the molecule CH₂=CHCH₂CH₂CH₃?

A. sp² - sp³

B. sp² - sp²

C. sp³ - sp³

D. sp - sp²

VSEPR Theory

• Model used in chemistry to predict the Geometry of individual molecules from the number of electron pairs surrounding their central atoms

• Electron pairs located in bonds REPEL to affect the geometry of the bonds in a molecule

Steric #

lone pair + sigma bond

If steric number = 4

• sp³

Tetrahedral arrangement of electron pairs

• One lone pair → Trigonal pyramidal

• Two lone pair → Bent

• No lone pair → Tetrahedral

If steric number = 3

• sp²

Trigonal Planar arrangement of electron pairs

• No lone pair → Trigonal Planar

• One lone pair → Trigonal Planar

If steric number = 2

• sp

Linear arrangement of electron pairs

• Linear

• sp³

• Steric # 4

• Lone pairs: 0

• Geometry: TETRAHEDRAL

• Angle: 109.5º

• Example: METHANE

• sp³

• Steric # 4

• Lone pairs: 1

• Geometry: Trigonal pyramidal

• Angle: 107º

• Example: Ammonia

• sp³

• Steric # 4

• Lone pairs: 2

• Geometry: Bent

• Angle: 104.5º

• Example: Water

• sp²

• Steric # 3

• Lone pairs: 0

• Geometry: Trigonal Planar

• Angle: 120º

• Example: Formaldehyde

• sp²

• Steric # 3

• Lone pairs: 1

• Geometry: Bent

• Angle: 118º

• Example: Ozone

• sp

• Steric # 2

• Lone pairs: 0

• Geometry: Linear

• Angle: 180°

• Example: Hydrogen Cyanide

note: this is most likely to happen in triple bonds

TRIGONAL PLANAR

Predict the shape:

1. Check for bonds (lone pair, sigma bonds)

2. Priority is central atom

3. The molecule below is Boron Trifluoride

4. Remember: Steric # = lone pair + sigma bonds

5. As you can see, there are 3 sigma bonds

6. Boron has no lone pairs: only the Trifluoride

7. 0 + 3 = 3

8. Steric number is 3; sp² Hybridization

9. If 0 lone pair, the shape is ____

LINEAR

Predict the shape:

1. Check for bonds (lone pair, sigma bonds)

2. Priority is central atom

3. Remember: Steric # = lone pair + sigma bonds

4. As you can see, there are 2 sigma bonds

5. Carbon has no lone pairs: only the 2 oxygen

6. 0 + 2 = 2

7. Steric number is 2; sp Hybridization

8. There is only 1 sp so the shape is ____

IUPAC Prefixes 1-10

• 1 - METH

• 2 - ETH

• 3 - PROP

• 4 - BUT

• 5 - PENT

• 6 - HEX

• 7 - HECT

• 8 - OCT

• 9 - NON

• 10 - DEC

IUPAC Prefixes 11-20

• 11 - UNDEC

• 12 - DODEC

• 13 - TRIDEC

• 14 - TETRADEC

• 15 - PENTADEC

• 16 - HEXADEC

• 17 - HEPTADEC

• 18 - OCTADEC

• 19 - NONADEC

• 20 - EICOS

2-Hydroxypropanoic acid

What is the IUPAC name of lactic acid?

Description: Milk acid; produced by bacteria in decomposing plants and milk products

• There is 3 carbons: so the prefix is PROP

• Since it is a carboxylic acid - this is propanoic acid

• In carbon #2 there is an OH - hydroxy group

• 2-Hydroxypropanoic acid

B. Lactic acid

Hydroxy acid

A. Pyruvic acid

B. Lactic acid

C. Acetic Acid

D. Sulfuric Acid

D. 2-hydroxyl propionic acid

What could be another name for lactic acid?

A. Bichloroacetic acid

B. Dihydroxy succinic acid

C. Ethanedioic acid

D. 2-hydroxyl propionic acid

B. Lactic Acid

Select the carbohydrate used as acidulant, especially in infant feeding formula:

A. Mannitol

B. Lactic Acid

C. Citric Acid

D. Tartaric Acid

Common Prefixes

No. of Carbon → Prefix

• 1 - FORM

• 2 - ACET

• 3 - PROPION

• 4 - BUTYR

• 5 - VALER

• 6 - CAPRO

• 7 - ENANTH

• 8 - CAPRYL

• 9 - PELARGON

• 10 - CAPR