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Organic

Chemistry

Aka – Carbon Chemistry

Organic Molecules are Everywhere!� Common examples:

� Ethanol = additive

in gasoline and the

alcohol in alcoholic drinks

� Acetic acid = vinegar

� Butane in

some lighters (others are pentane

– also organic!)

� Sucrose = Sugar� Natural gas

What Makes Carbon so Special?

o structure of carbon allows it to make 4

bonds (and ALWAYS make 4 bonds)

o Can bond with itself to make long chains

Alkanes:

�contain only single bonds

�are also called saturated (filled with only

single bonds in the carbon chain)

�General formula CnH2n+2

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Naming Alkanes and Branching Alkanes

1. Find the longest chain of carbons bound together

2. Use prefixes to indicate number of carbons in the longest chain

3. Use the suffix (ending) “ane” to indicate only single bonds are present

4. Number the carbon chain to make the lowest possible numbers

5. Use numbers and prefixes to indicate the position of any branched chains (in alphabetical order)

Example:

•Branches

– 1 single carbon group on carbon #3

∴ “3-methyl”

3-methylpentane

�Longest chain

= 5 carbons

∴ Pent

�Only single bonds = “ane”

�Number the chain

Alkenes, Alkynes,

and Cyclic

Hydrocarbons

next!

Alkenes and Alkynes

- unsaturated hydrocarbons!

�Alkenes = at least 1 double bond

�Alkynes = at least 1 triple bond

�When naming, follow same process as alkanes…

�Except…

�Use different ending “ene” or “yne”

�Need a number to indicate where the double or triple bond is

�if the double bond is between C2 and C3 we use the number 2 in the name

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Example:

�Longest Chain?

�Longest Chain = 6 carbons (must include

double bond!) (hexene)

�Number the chain to make the lowest

number for the double bond

�Double bond between C2 and C3∴ Parent chain = 2-hexene

1 2

3

4 5 6

�Branches?

� ethyl group on carbon 3

�So it is called…

1 2

3

4 5 6

3 – ethyl – 2 – hexene

You try!

�See if you can name the following

molecules

It is….ethyne (if there is no other option of where to put the triple bond, you

don’t need a number)

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You try!

It is….3 – methyl – 2 – hexene

You try!

It is….5,5 – dimethyl – 3 – heptyne

Cyclic Hydrocarbons�There is a carbon “ring” present

�Name just like before, only the parent chain gets the prefix “cyclo” added on

�Example:

�This is called…methylcyclopentane (no

number is required since no matter where

you put the methyl group it would be the

same molecule)

Geometry of Alkenes

� Isomers – molecules with the same

formula, but different arrangement of the

atoms

� Cis-Trans Isomerization:

� Double bonds “trap” a molecule in a specific

shape

� When different groups are across a double bond,

different isomers form (either cis or trans)

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The two isomers for 2-pentene

� Cis = the “same” side

� The non-hydrogen groups are on the same side of

the double bond

� Trans = across (like the Trans Canada Highway)

� The non-hydrogen groups are across from each

other in the double bond

Quiz on Alkanes, Alkenes,

Alkynes, and Cyclic

Hydrocarbons tomorrow!