ORGANIC CHEMISTRY: THE HYDROCARBON

Some Definition

Organic chemistry is the science of carbon compounds, which includes the synthesis of these compounds and the study of the reactions of these compounds.
Organic compounds are compounds which contain carbon (with the exception of carbon dioxide, carbon monoxide, carbonates, carbides, and some of cyanides).
Proteins, fats, carbohydrates, vitamins, hormones, cellulose, anesthetics, antibiotics, and enzymes are some examples of organic compounds.

Carbon Bonding
• Carbon atoms can unite with one another by sharing one or more pairs of electron to form chain or cyclic molecules.
• Carbon atoms with four valence electrons can form four covalent bonds.

Hydrocarbons
Hydrocarbons are compounds that contain only carbon and hydrogen. Types of hydrocarbon:
1. Alkanes CnH2n+2
2. Cycloalkanes CnH2n+2-2y ; where y is the number of rings.
3. Alkenes CnH2n
4. Alkynes CnH2n-2
5. Benzene (aromatic) hydrocarbon

Types of Hybridization for Hydrocarbons

Hydrocarbon Hybridization of the carbon
Alkane Sp3
Alkene Sp2
Alkyne Sp

Alkanes

General formula CnH2n+2
CH4 methane
C2H6 ethane
C3H8 propane
C4H10 butane
C5H12 pentane
C6H14 hexane
C7H16 heptane
C8H18 octane
C9H20 nonane
C10H22 dekane

Cycloalkanes
General formula CnH2n+2-2y

C₃H₆ cyclopropane

C₄H₈ cyclobutane

C₅H₁₀ cyclopentane

C₆H₁₂ cyclohexane

Alkenes

General formula C_nH_2n

C₂H₄ ethane (ethylene)

C₃H₄ propene (propylene)

C₄H₈ butene

C₅H₁₀ pentene

Alkynes

General formula

C₂H₂ ethyne (acetylene)

C₃H₄ propyne

C₄H₆ butyne

C₅H₁₀ pentyne

Structural formulas of alkanes

Structural formulas of alkenes and alkynes

Benzene

Resonance

Resonance is a result of the fact that the correct bonding in a molecule is a hybrid (mixture) of all the possible electron structures which can be written.

Resonance energy is the energy required to change a mole of hybrid molecules to a mole of molecules having the single, conventional valence-bond formula.

Benzene, toluene, and other aromatics

Isomerism

Isomers are compounds which have the same molecular formulas, but different structural formulas.

Isomeric compounds can differ both chemically and physically. They can have difference in melting points, boiling points, refractive index, and chemical activity.

to be continued.....