Brief! Brief! Organic ChemistryOrganic Chemistry

for APfor AP

AlkanesAlkanes

• Hydrocarbon chains where all the bonds Hydrocarbon chains where all the bonds between carbons are SINGLE bondsbetween carbons are SINGLE bonds

• Name uses the ending –Name uses the ending –aneane

• Examples: MethExamples: Methaneane, Prop, Propaneane, But, Butaneane, , OctOctaneane, 2-methylpent, 2-methylpentaneane

Prefixes for # of CarbonsPrefixes for # of Carbons

11 MethMeth 66 HexHex

22 EthEth 77 HeptHept

33 PropProp 88 OctOct

44 ButBut 99 NonNon

55 PentPent 1010 DecDec

EndingsEndings

• Alkanes (all C-C single bonded parent Alkanes (all C-C single bonded parent chain) end in chain) end in –ane–ane– MethMethaneane CHCH44

– EthEthaneane CC22HH66

– PropPropaneane CC33HH88

• Attached carbon groups (substituents) end Attached carbon groups (substituents) end in in –yl–yl– MethMethylyl CH CH33 - -– EthEthylyl CHCH33CHCH22--– PropPropylyl CH CH33CHCH22CHCH2 2 –  –      3-ethylpentane

Names of attached groupsNames of attached groups

• Carbon (alkCarbon (alkylyl) groups) groups– MethMethylyl CH CH33 - -– EthEthylyl CHCH33CHCH22--– PropPropylyl CH CH33CHCH22CHCH2 2 ––

• HalogensHalogens– Fluoro (F-)Fluoro (F-)– Chloro (Cl-)Chloro (Cl-)– Bromo (Br-)Bromo (Br-)– Iodo (I-)Iodo (I-)

Designate the LocationDesignate the Location

• Designate the location (number of the carbon on the parent chain) for each attached group

1 2 3 4 5

2-methyl

Some Simple AlkanesSome Simple Alkanes

• 2-methylpentane2-methylpentane

• 3-ethylhexane3-ethylhexane

• 2,2-dimethylbutane2,2-dimethylbutane

• 2,3-dimethylbutane2,3-dimethylbutane

Structural FormulasStructural Formulas

• “Lazy” way to write the Hydrogens

• Instead of drawing the bonds, just state how many hydrogens are attached

• NOTE: The bonds are between CARBONS in a parent chain, and not hydrogens!

Structural FormulaLewis Structure

Drawing and Naming CycloalkanesDrawing and Naming Cycloalkanes

Cycloalkanes are represented by polygons. A Cycloalkanes are represented by polygons. A triangle represents cyclopropane, a square triangle represents cyclopropane, a square represents cyclobutane, a pentagon represents represents cyclobutane, a pentagon represents cyclopentane, and so on.cyclopentane, and so on.

IsomersIsomers

• Straight chain alkanes:Straight chain alkanes: An alkane that An alkane that has all its carbons connected in a row.has all its carbons connected in a row.• Branched chain alkanes:Branched chain alkanes: An alkane An alkane that has a branching connection of that has a branching connection of carbons.carbons.• Isomers: Isomers: Compounds with same Compounds with same molecular formula but different molecular formula but different structures.structures.

• However, carbons in butane (CHowever, carbons in butane (C44HH1010) can ) can be arranged in two ways; four carbons in a be arranged in two ways; four carbons in a row (linear alkane) or a branching row (linear alkane) or a branching (branched alkane). These two structures (branched alkane). These two structures are two isomers for butane.are two isomers for butane.

•Different isomers are completely different Different isomers are completely different compounds. They have different structures, compounds. They have different structures, different physical properties such as melting point different physical properties such as melting point and boiling point, and may have different and boiling point, and may have different physiological properties.physiological properties.

Learning CheckLearning Check

• Draw all possible structural isomers of C5H12

Alkenes and Alkynes

• Unsaturated– contain carbon-carbon double and triple bond to

which more hydrogen atoms can be added.

• Alkenes: carbon-carbon double bonds• Alkynes: carbon-carbon triple bonds.

Naming Alkenes and Alkynes

When the carbon chain has 4 or more C atoms, number the chain to give the lowest number to the double or triple bond.

1 2 3 4

CH2=CHCH2CH3 1-butene

CH3CH=CHCH3 2-butene

CH3CCCH3 2-butyne

Aromatic Compounds and Benzene

Aromatic compounds contain benzene.

Benzene, C6H6 , is represented as a six carbon

ring with 3 double bonds.

Two possible resonance structures can be drawn to show benzene in this form.

H

H

H

H

H

H

HH

H

H

H

H

Functional Groups