25-3: Hydrocarbons25-3: Hydrocarbons25-4: Saturated and 25-4: Saturated and

Unsaturated HydrocarbonsUnsaturated Hydrocarbons

HydrocarbonHydrocarbon

Organic molecule that contains only Organic molecule that contains only hydrogen and carbonhydrogen and carbonProperties:Properties:– All bonds are nonpolar, so molecule is All bonds are nonpolar, so molecule is

nonpolarnonpolarAre poor conductorsAre poor conductorsHave low densityHave low densityDo not dissolve in waterDo not dissolve in water

– Found deep within the Earth as natural gas Found deep within the Earth as natural gas and petroleum (fossil fuels)and petroleum (fossil fuels)

Types of formulasTypes of formulas

Molecular formula: gives symbols and numbers Molecular formula: gives symbols and numbers of atoms presentof atoms present– Ex: butane is CEx: butane is C44HH1010

Structural formula: shows how the atoms are Structural formula: shows how the atoms are bonded together in a two dimensional waybonded together in a two dimensional way– ButaneButane

Condensed structural formula: shows only how Condensed structural formula: shows only how carbon atoms are bondedcarbon atoms are bonded– Butane CHButane CH33CHCH22CHCH22CHCH33

AlkanesAlkanes

Hydrocarbons with only single bondsHydrocarbons with only single bonds

Names end in –aneNames end in –ane

General formula: CGeneral formula: CnnHH2n+22n+2

Is a saturated hydrocarbon; all carbon Is a saturated hydrocarbon; all carbon bonds are filled to capacity with hydrogensbonds are filled to capacity with hydrogens

Alkane SeriesAlkane Series

MethaneMethane

EthaneEthane

PropanePropane

ButaneButane

PentanePentane

HexaneHexane

HeptaneHeptane

OctaneOctane

NonaneNonane

decanedecane

CHCH44

CC22HH66

CC33HH88

CC44HH1010

CC55HH1212

CC66HH1414

CC77HH1616

CC88HH1818

CC99HH2020

CC1010HH2222

Branched AlkanesBranched Alkanes

1.1. Identify the longest continuous carbon Identify the longest continuous carbon chain. This is the parent chain and is chain. This is the parent chain and is named as a regular alkane.named as a regular alkane.

2.2. Identify the shorter chain. Give this Identify the shorter chain. Give this chain a number (from the carbon that it is chain a number (from the carbon that it is bonded to) and name it as an alkyl group bonded to) and name it as an alkyl group (methyl, ethyl, propyl, butyl)(methyl, ethyl, propyl, butyl)

3.3. ExamplesExamples

Conformations Conformations

Two structures that differ only by one or Two structures that differ only by one or more bond rotationsmore bond rotations

ExamplesExamples

Structural IsomersStructural Isomers

Two structures that have the same Two structures that have the same molecular formula, but their atoms bond in molecular formula, but their atoms bond in different orders.different orders.

ExamplesExamples

CycloalkanesCycloalkanes

Cyclic hydrocarbons: hydrocarbons that Cyclic hydrocarbons: hydrocarbons that contain a carbon ringcontain a carbon ring

If they contain all single bonds, then they If they contain all single bonds, then they are cycloalkanesare cycloalkanes

Unsaturated HydrocarbonsUnsaturated Hydrocarbons

Contain at least one double or triple bond Contain at least one double or triple bond between carbon atoms.between carbon atoms.

AlkenesAlkenes

Contain at least one double bond.Contain at least one double bond.

General formula: CGeneral formula: CnnHH2n2n

In naming, name them just like alkanes, In naming, name them just like alkanes, just give a number to designate the just give a number to designate the position of the double bond AND they end position of the double bond AND they end in –ene.in –ene.

Example: apples produce ethene gas as Example: apples produce ethene gas as they ripen.they ripen.

AlkynesAlkynes

Contain at least one triple bond.Contain at least one triple bond.

General formula: CGeneral formula: CnnHH2n-22n-2

In naming, name them just like alkanes, In naming, name them just like alkanes, just give a number to designate the just give a number to designate the position of the triple bond AND they end in position of the triple bond AND they end in –yne.–yne.

Ethyne is used in torches – also called Ethyne is used in torches – also called acetylene.acetylene.

BenzeneBenzene

Draw it.Draw it.

Compounds that have a benzene ring in it Compounds that have a benzene ring in it are called aromatic compounds (they are called aromatic compounds (they usually smell good!)usually smell good!)

Examples of aromatic compounds include: Examples of aromatic compounds include: cloves, vanilla beans, and almonds. cloves, vanilla beans, and almonds.