Organic Chemistry

Simple Organic FamiliesOrganic Nomenclature

Organic Molecules • Organic chemistry is the chemistry of

carbon compounds.• Carbon has the ability to form long

chains.• Without this property, large

biomolecules such as proteins, lipids, carbohydrates, and nucleic acids could not form.

• Carbon is the only element capable of forming stable chains of atoms bonded through single-double-triple bonds.

Structure of Carbon Compounds• There are three hybridization states and geometries

found in organic compounds:– sp3 tetrahedral– sp2 trigonal planar– sp linear

HYDROCARBON FAMILIES• Divided into four groups based on the kinds

of carbon-carbon bonds present

#1. Alkanes#2. Alkenes#3. Alkynes#4. Aromatics

Alkanes

• Alkanes contain only single bonds.• They are also known as saturated hydrocarbons.– They are “saturated” with hydrogens, only contain single

bonds.

Common Alkanes

Writing Formulas for Alkanes• Lewis structures of alkanes to the left below.• They are also called structural formulas.• They are often not convenient to attempt to

write so condensed formulas are typically used.

Properties of Alkanes• The only force is the London dispersion force.• The boiling point increases with the length of the chain.

Structure of Alkanes• Carbons in alkanes are sp3 hybrids.• They have a tetrahedral geometry

and 109.5 bond angles.

Structure of Alkanes• There are only -bonds present in

alkanes.• There is free rotation about the C—C

bonds.

What is an Isomer? P. 1009

Isomers have the same molecular formulas, but the atoms are bonded in a different order.

STRAIGHT

STRAIGHT

ISO

MER

SIS

OM

ERS

Common Naming Schemes

• Common Names listed in 1st column.

• “ n “ indicates an isomer of the normal structure

• When a CH3 group branches, the isomer prefix –iso

• When another CH3 group branches, the isomer prefix -neo

-iso

-iso

-n

-n

-neo

AFTER THIS – CRAZY TOWN!

Organic Prefixes based on Carbon Chains

Organic Nomenclature• There are three parts to a compound name:– Base: This tells how many carbons are in the longest continuous

chain.– Suffix: This tells what type of compound it is.– Prefix: This tells what groups are attached to the chain.

Naming Simple Alkanes

Watch this link to learn to name simple alkanes!

Let’s try some!

How to Name a Compound

If there is more than one type of substituent in the molecule, list them alphabetically.

GOT IT??? YEAH RIGHT! WATCH THIS!

Cycloalkanes• Carbon can also form ringed structures.• Five- and six-membered rings are most stable.– They can take on conformations in which their bond angles are

very close to the tetrahedral angle.– Smaller rings are quite strained.

Reactions of Alkanes

• Alkanes are rather unreactive due to the presence of only C—C and C—H -bonds.

• Therefore, they make great nonpolar solvents.• Make great Combustion fuel!