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Introduction to Organic Chemistry

 

What is Organic Chemistry?

The chemistry of carbon containing compounds.

Why is Organic Chemistry important?

Pervasive in nature, chemical foundation of biology, and can improve our standard of living (medicines, plastics, pesticides)

How does Carbon Bond?

Carbon is able to form up to 4 bonds. Carbon can hybridize the 2s and the 3 2p orbitals into a new hybrid orbital (either sp3, sp2 or and sp)

-->Hybridization Tutorial<--

-->Sigma & Pi Bonding Tutorial<--

Each atom has a limited number of possibilities to satisfy octet:

 

    1. Nonbonding (electron pair localized on one atom)

 

    2. Bonding (electron pair shared between two atoms)

 

        a. Single bond (1 shared pair;sp3 hybridization)

 

        b. Double bond (2 shared pairs; sp2 hybridization)

 

        c. Triple bond (3 shared pairs; sp hybridization)

 

Why is it important that carbon can bond with itself?

 

It makes it possible for large number of organic molecules. Even more numerous than inorganic compounds.

 

What are sources of Organic Raw Materials?

 

Petroleum, coal, wood, and other plant and animal sources

 

What are some characteristics of organic compounds?

 

Polarity

Mostly Nonpolar, so they usually do not dissolve in water (e.g. oil).

 

Some however, are polar or slightly polar and do dissolve in water (e.g. acids and alcohols).

 

Electrolytes

Non electrolytes except for orgainic acids which are weak electrolytes.

 

Boiling/Melting Point

Usually they have a low melting point, due to weak intermolecular forces.

 

The melting point generally increases with an increase in the number of carbons.

 

Flash Animation Boiling Points

Melting (blue) and boiling (pink) points of the first 14 n-alkanes in C.

Melting point boiling points

Name Molecular
Formula
Melting
Point (oC)
Boiling
Point (oC)
State
at 25oC
methane CH4 -182.5 -164 gas
ethane C2H6 -183.3 -88.6 gas
propane C3H8 -189.7 -42.1 gas
butane C4H10 -138.4 -0.5 gas
pentane C5H12 -129.7 36.1 liquid
hexane C6H14 -95 68.9 liquid
heptane C7H16 -90.6 98.4 liquid
octane C8H18 -56.8 124.7 liquid
nonane C9H20 -51 150.8 liquid
decane C10H22 -29.7 174.1 liquid
undecane C11H24 -24.6 195.9 liquid
dodecane C12H26 -9.6 216.3 liquid
eicosane C20H42 36.8 343 solid
triacontane C30H62 65.8 449.7 solid

 

Reaction Rate

generally slow due to strong covalent bonding between carbon atoms

 

 


 

 

 

 

What are Hydrocarbons?

A hydrocarbon is a chemical compound that consists only of the elements carbon (C) and hydrogen (H). Hydrocarbons contain a backbone consisting of carbon atoms, called a carbon skeleton with hydrogen atoms attached to that backbone. Hydrocarbons, which are combustible, are the main components of fossil fuels, which include petroleum, coal, and natural gas. The most abundant hydrocarbon is methane.

 

What are Isomers?

Compounds that have the same molecular formula but a different structural formula.

isomers of propanol

They all have a molecular formula of C3H8O, but have different structures. So as the number of carbons increase the number of Isomers increase.

Name Molecular
Formula
Structural
Formula
Isomers Name Molecular
Formula
Structural
Formula
Isomers
methane CH4 CH4 1 hexane C6H14 CH3(CH2)4CH3 5
ethane C2H6 CH3CH3 1 heptane C7H16 CH3(CH2)5CH3 9
propane C3H8 CH3CH2CH3 1 octane C8H18 CH3(CH2)6CH3 18
butane C4H10 CH3CH2CH2CH3 2 nonane C9H20 CH3(CH2)7CH3 35
pentane C5H12 CH3(CH2)3CH3 3 decane C10H22 CH3(CH2)8CH3 75

What does saturated and unsaturated mean?

A saturated hydrocarbon (or other organic molecule) has utilized all of its bonding electrons to make single bonds to other atoms. It can not make additional bonds without cutting off part of the existing molecule. saturated

An unsaturated hydrocarbon (or other organic molecule) contains double or triple bonds between certain atoms. These bonds may be broken and new atoms attached without disrupting the existing skeleton of the hydrocarbon.

What is a homologous series?

In chemistry, a homologous series is a series of organic compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and shows a gradation in physical properties as a result of increase in molecular size and mass (see relative molecular mass). For example, ethane has a higher boiling point than methane since it has more Van der Waals forces with neighboring molecules. This is due to the increase in the number of atoms making up the molecule. Organic compounds in the same homologous series vary by a CH2.

What are the general formulas?

Homologous series General formula Example Functional group
Alkanes CnH2n + 2 (n more than or equal to 1) CH4, n = 1
Alkenes CnH2n (n more than or equal to 2) C2H4, n = 2 C = C
Alkynes CnH2n − 2 (n more than or equal to 2) C2H2, n = 2 C ≡ C
Alcohols CnH2n + 2O (n more than or equal to 1) CH4O, n = 1 - OH
Carboxylic acids CnH2nO2 (n more than or equal to 1) CH2O2, n = 1 - COOH

on to Naming Alkanes

back to Organic Links

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