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HydrocarbonsUnsaturated hydrocarbons

– Double and triple bonds between carbons

– Not every carbon has each of its 4 electrons bonded to 4 different atoms

– More chemically reactive than saturated compounds, or alkanes

– Unsaturated hydrocarbons include alkenes (double bonds) and alkynes (triple bonds)

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Parent hydrocarbon prefixes# Carbon atoms

Example

1 meth- CH4 methane

2 eth- C2H6 ethane

3 prop- C3H8 propane

4 but- C4H10 butane

5 pent- C5H12 pentane

6 hex- C6H14 hexane

7 hept- C7H16 heptane

8 oct- C8H18 octane

9 non- C9H20 nonane

10 dec- C10H22 decane

As attached groups:

Functional group

Group name

-CH3 methyl

-C2H5 ethyl

-C3H7 propyl

-C4H9 butyl

-C5H11 pentyl

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Naming Organic Compounds1. Name the parent hydrocarbon: Use the

LONGEST STRAIGHT chain of carbon atoms.2. Add the name of the alkyl groups attached to the

chain. If more than one group is attached, use the proper numerical prefix to indicate how many groups are attached. (2=di, 3-tri,etc.)

3. Assign numbers to the carbons in the parent chain. Assign so that attached groups are at the lowest number possible.

4. Insert the numbers in front of the proper group.5. Separate position numbers from names with

hyphens.

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Example: Naming Organic Compounds1. Name the parent hydrocarbon.

CH3 – CH – CH2 – CH – CH – CH3 hexane

CH3 CH3 CH3

2. Add the name of the alkyl groups attached to the chain. 3 methyl groups: trimethylhexane 3. Assign numbers to the carbons in the parent chain.6 5 4 3 2 1

CH3 – CH – CH2 – CH – CH – CH3

CH3 CH3 CH3

4-5. Insert position numbers and add hyphens.2,3,5-trimethylhexane

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Name the following compounds1. CH3 – CH – CH2 – CH2 – CH3

CH3

2. CH3 – CH – CH2 – CH2 – CH – CH3

| |

CH3 CH3

3. CH3 – CH – CH2 – CH2 – CH3

CH2

CH2

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Unsaturated hydrocarbons

• Single bond between carbons: -ane CnH2n+1

• Double bond between carbons: -ene CnH2n

• Triple bond between carbons: -yne CnHn

• Examples:

C

H

HH C

HH

H

ethaneC2H6

C CH H

H H

etheneC2H4

CCH H

ethyneC2H2

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Other Functional GroupsCompound Formula Example

Alcohol R-OH hydroxyl group 1-propanol

Alkyl Halide -X X = any halide 1,2-dibromopropane

Ether R-O-R’ one oxygen bonded to 2 hydrocarbon groups

diethyl ether CH3-CH2 –O--CH2--CH3

Aldehyde O ||R-C-H

Carbonyl group attached to end carbon

Ethanal O || CH3—C--H

Ketone O ||R-C-R’

Carbonyl group attached to a middle carbon

2-propanone O || CH3—C-- CH3

Carboxylic Acid O ||R-C-OH

Carboxyl group ethanoic acid O || CH3—C—OH

Ester O ||R-C-O-R’

Carboxyl group without the H

methyl ethanoate O || CH3—C—O-- CH3

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Cyclic Compounds• Cycloalkanes

– Saturated carbons joined in a ring

– Example is cyclohexane, C6H12

– Add cyclo- to beginning of name if the alkane is known to be arranged in a circle (CnH2n). No position number is needed if only one alkyl group is attached.

• Aromatic compounds– Unsaturated: Contains 3 double bonds

– Example is benzene, C6H6

C-H

C-H

C-H

H-C

H-C

H-Cbenzene1-ethyl-4-methylbenzene

CH3CH2- -CH3

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Addition Reactions• Water adds to ethene: The double bond is broken and

an H attaches to one carbon and the OH attaches to the other carbon.

H H H H

C C + H-OH H-C-C-H

H H H H• Ethene can add to itself, breaking double bonds to

attach to one molecule after another.

• A monomer is a small unit; when additional monomers are attached repeatedly, a long-chain polymer is formed.

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Addition Polymers• Polyethylene is a polymer made from the monomer

ethene. Zip-lock bags are usually made from low-density polyethylene.

• Common polymer variations replace one of ethene’s hydrogens with another unit, such as a halogen atom (F or Cl), Cyanide (CN), or benzene (C6H6).

– Vinyl chloride polyvinyl chloride– Acrylonitrile polyacrylnitrile– Styrene polystyrene

• Atoms that compose the monomers determine the properties of the polymer.