3Hydrocarbons. . . Contain only hydrogen and carbon. Types: Alkane: single bonds; saturated (largest possible number of hydrogens/carbon atom. [CnH2n+2]Alkene: one or more carbon-carbon double bond. Unsaturated hydrocarbon.Alkyne: one carbon-carbon triple bond. Unsaturated hydrocarbon.Aromatic: carbon atoms connected in a planar ring. Unsaturated hydrocarbon.
4Hydrocarbons. . . Relatively nonpolar. (covalent bonds) Insoluble in water. (like dissolves like)Less volatile with increasing molar mass. (because of London dispersion forces)
5Alkanes. . . [CnH2n+2]Methane: CH4 major component of natural gas; home heating; gas stoves; hot water heatersEthane: C2H6Propane: C3H8 used for home cooking and heating; gas grillsButane: C4H10 disposable lighters and fuel canisters for gas camping stoves.
6Name consists of. . . 1. Prefix 2.Parent 3. Suffix Where are the substituents?2.ParentHow many carbons in the longest chain?3. SuffixWhich family?If two different chains of equal length are present:choose the one with the larger number of branch points as the parent.
7pent=5; hex=6; hept=7; oct=8; non=9; dec= 10 Rules for naming alkanes Longest continuous chain of carbon atoms gives the root name1. For alkanes, add –ane to the root:Meth: CEth: C2Prop: C3But: C42. For alkanes beyond butane, use the Greek root for the number of carbons then add -ane to the end.C-C-C-C-C-C = hexanepent=5; hex=6; hept=7; oct=8; non=9; dec= 10
8Group(s) added in place of a removed hydrogen. SubstituentGroup(s) added in place of a removed hydrogen.
9Alkanes as a substituent group. . . Alkyl substituents:1. Remove a hydrogen from the alkane.C2H6 is ethane2. Drop the -ane and add -yl.-C2H5 is ethyl
10Positions of substituent groups are specified by numbering the longest chain sequentially. (Use the lowest number for the position of the substituent group)The location and name of the substituent group is followed by root alkane name.CC-C-C-C-C-C3-methylhexane
12Substituents in alphabetical order. Use di-, tri-, etc. to indicate multiple identical substituents.
13Practice. . .write skeletal and condensed formulas. 2,3-dimethylhexane2-ethyl-3-methylpentane4-ethyl-3,5-dimethylnonane4-tert-butylheptane2,3-dimethylpentane
14Cyclic Alkanes. . . CnH2n Cycloalkanes Smaller than five carbons, very reactive.Rings of carbon atoms.IsomersCis: both substituents are on the same side of the ring.Trans: substituents are on opposite sides of the ring.
19Reactions of AlkanesCombustion: react with oxygen produce carbon dioxide and waterSubstitution: halogen atoms replace hydrogen atomsDehydrogenation reactions:hydrogen removed forms double bond there unsaturated hydrocarbon is the product
22Alkenes. . .1. Root hydrocarbon (longest chain containing double bond) name ends in –ene.2. More than three carbon atoms, the location of the double bond is indicated by the lowest numbered carbon atom in the bond. If equidistant: begin at end closer to substituent group.CH2=CHCH2CH3 1-buteneCH3CH=CHCH butene3. More than one double bondIndicate the position of each and use –diene, triene, tetraene. . .
23Cycloalkenes. . . Name same as alkenes. Number so double bond is between C1 and C2 and the first substituent has the lowest number possible.
24Practice. . .write the skeletal formula and name. CH2=CHCH(CH3)C(CH3)(CH3)CH3CH3CH2CH=C(CH3)CH2CH3CH3CH=CHCH(CH3)CH=CHCH(CH3)CH3
27Alkynes. . .Unsaturated hydrocarbons contain atleast one triple carbon-carbon bond.-yne replaces –ane.Begin numbering chain at end closest to triple bond.More than one bond: -diynes, -triynes.Double and triple bonds: -enynesStart numbering from end nearer first bond. (if there is a choice. Usually double bonds get lower numbers than triple.)
30Reactions of Alkenes and Alkynes. . . Addition reactions: double bond broken and new bonds formed to atoms added.Hydrogenation reactions: addition of hydrogen atomsHalogenation: addition of a halogenElimination:one reactant splits apart to give two products.Substitutions: two reactants exchange parts to give two new products.Rearrangement:one reactant undergoes a reorganization of bonds and atoms to give a new product.
31Aromatic Hydrocarbons. . . Benzene and its structural relatives Monosubstituted benzene: named as other hydrocarbons, with benzene as parent name.If substituent larger than ring (six carbons) : benzene becomes substituent group called phenyl.Disubstituted benzene: ortho:1,2 meta-1,3 para-1,4More than two: number the position of each substituent group.
32Alcohols. . . Alcohols: presence of an –OH (hydroxyl group) Nomenclature: replace final -e of parent hydrocarbon with –ol.(parent: longest chain containing –OH)Position of –OH specified by number- lowest number.Classified by: number of hydrocarbon fragments bonded to carbon where –OH group is attached.eg. C-C-C-C or C-C-C-C or CC-C-C
38Aldehydes. . . Nomenclature: remove –e replace with –al. Longest chain as base name,must contain the carbonyl group. Aldehyde carbon assigned number 1, when subtituent positions are listed in the name.Bonded to at least one hydrogen atom.Number indicates position of carbonyl group.
45Carboxylic Acids. . . Two systems: aldehyde and alcohol Derived from open chain alkanes:Carboxyl carbon is always C1.Replace terminal –e of alkane with –oic acid.-COOH group bonded to a ring, the suffix –carboxylic acid is used. The carboxylic acid carbon is attached to C1 and is not itself numbered in this system.