What is Organic Chemistry?
*Definition*: The study of carbon compounds and their reactions. Carbon is
unique because it forms 4 covalent bonds, chains, rings, and can bond to H, O, N,
S, P, halogens.
*Why it matters*:
- Life is organic chemistry: DNA, proteins, lipids, carbs
- Fuels, plastics, medicines, dyes, food all rely on it
*Key concepts*:
- *Hybridization*: sp³ = tetrahedral, sp² = trigonal planar, sp = linear
- *Bond polarity*: C-H is non-polar, C-O and C-N are polar. Polarity drives
reactions
- *Lewis structures & resonance*: Electrons delocalize over multiple atoms.
Example: benzene, carboxylate ion 2: Hydrocarbons – Alkanes, Alkenes, Alkynes
*Alkanes*: CₙH₂ₙ₊₂, single bonds only. Inert, used as fuels. Nomenclature:
methane, ethane, propane. Isomers exist for C4+.
*Alkenes*: C=C double bond. More reactive. Cis/trans isomerism. Key reaction:
addition reactions – H₂, HX, H₂O, Br₂. Markovnikov’s rule.
*Alkynes*: C≡C triple bond. Terminal alkynes are acidic. Reactions: reduction to
alkenes/alkanes, hydration to ketones.
*Aromatics*: Benzene C₆H₆. 6π electrons, planar, very stable. Substitution
reactions, not addition. Electrophilic aromatic substitution: nitration,
sulfonation, halogenation, Friedel-Crafts.
3: Functional Groups & Nomenclature
Functional groups define reactivity. Key ones:
Group Structure Example Properties
Alcohol -OH Ethanol H-bonding, polar, acidic pKa ~16
Aldehyde -CHO Acetaldehyde Easily oxidized to acid
Ketone -C=O Acetone Less reactive than aldehydes
Carboxylic acid -COOH Acetic acid Acidic pKa ~4-5, H-bond dimer
Amine -NH₂ Aniline Basic, nucleophilic
Ester -COOR Ethyl acetate Fragrances, fats
Amide -CONH₂ Acetamide Stable, found in proteins
*IUPAC rules*: Find longest chain, number for lowest substituent numbers, name
*Definition*: The study of carbon compounds and their reactions. Carbon is
unique because it forms 4 covalent bonds, chains, rings, and can bond to H, O, N,
S, P, halogens.
*Why it matters*:
- Life is organic chemistry: DNA, proteins, lipids, carbs
- Fuels, plastics, medicines, dyes, food all rely on it
*Key concepts*:
- *Hybridization*: sp³ = tetrahedral, sp² = trigonal planar, sp = linear
- *Bond polarity*: C-H is non-polar, C-O and C-N are polar. Polarity drives
reactions
- *Lewis structures & resonance*: Electrons delocalize over multiple atoms.
Example: benzene, carboxylate ion 2: Hydrocarbons – Alkanes, Alkenes, Alkynes
*Alkanes*: CₙH₂ₙ₊₂, single bonds only. Inert, used as fuels. Nomenclature:
methane, ethane, propane. Isomers exist for C4+.
*Alkenes*: C=C double bond. More reactive. Cis/trans isomerism. Key reaction:
addition reactions – H₂, HX, H₂O, Br₂. Markovnikov’s rule.
*Alkynes*: C≡C triple bond. Terminal alkynes are acidic. Reactions: reduction to
alkenes/alkanes, hydration to ketones.
*Aromatics*: Benzene C₆H₆. 6π electrons, planar, very stable. Substitution
reactions, not addition. Electrophilic aromatic substitution: nitration,
sulfonation, halogenation, Friedel-Crafts.
3: Functional Groups & Nomenclature
Functional groups define reactivity. Key ones:
Group Structure Example Properties
Alcohol -OH Ethanol H-bonding, polar, acidic pKa ~16
Aldehyde -CHO Acetaldehyde Easily oxidized to acid
Ketone -C=O Acetone Less reactive than aldehydes
Carboxylic acid -COOH Acetic acid Acidic pKa ~4-5, H-bond dimer
Amine -NH₂ Aniline Basic, nucleophilic
Ester -COOR Ethyl acetate Fragrances, fats
Amide -CONH₂ Acetamide Stable, found in proteins
*IUPAC rules*: Find longest chain, number for lowest substituent numbers, name
