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Hydrocarbons. Unsaturated 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
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Hydrocarbons Unsaturated 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)
Naming Organic Compounds • Name the parent hydrocarbon: Use the LONGEST STRAIGHT chain of carbon atoms. • 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.) • Assign numbers to the carbons in the parent chain. Assign so that attached groups are at the lowest number possible. • Insert the numbers in front of the proper group. • Separate position numbers from names with hyphens.
Example: Naming Organic Compounds • Name the parent hydrocarbon. CH3 – CH – CH2 – CH – CH – CH3 hexane CH3 CH3 CH3 • Add the name of the alkyl groups attached to the chain. 3 methyl groups: trimethylhexane • 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
Name the following compounds • 1. CH3 – CH – CH2 – CH2 – CH3 • CH3 • CH3 – CH – CH2 – CH2 – CH – CH3 | | • CH3 CH3 • 3. CH3 – CH – CH2 – CH2 – CH3 • CH2 • CH2
H H H H C C H C C H H C C H H H H H ethene C2H4 ethyne C2H2 ethane C2H6 Unsaturated hydrocarbons • Single bond between carbons: -aneCnH2n+1 • Double bond between carbons: -eneCnH2n • Triple bond between carbons: -yneCnHn • Examples:
H-C C-H H-C C-H CH3CH2- -CH3 C-H H-C 1-ethyl-4-methylbenzene benzene 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
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.
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.