3 Bond Angles in Alkenes and Alkynes According to VSEPR theory:Three groups in a double bond are bonded at 120° angles.Alkenes are flat, because the atoms in a double bond lie in the same plane.The groups attached to a triple bond are at 180° angles.
4 Physical properties Similar to alkanes Solubility Soluble in nonpolar solventsNot soluble in waterLow density, boiling point and melting pointProperties vary based on chain sizeInteresting physical property.Alkenes with several double bonds will have a color associated with them.
5 Colored alkenes lycopene - red of tomato, paprika and watermelon CH3HClycopene - red of tomato, paprika and watermelonCH3HC-carotene, yellow of carrots and yams
6 Naming Alkenes The names of alkenes Use the corresponding alkane name. Change the ending to ene.Alkene IUPAC CommonH2C=CH2 ethene ethyleneH2C=CH─CH3 propene propylenecyclohexene
12 Naming Alkenes with Substituents CH3│Write the IUPAC name for CH3─CH─CH=CH─CH3STEP 1 Name the longest carbon chain penteneSTEP 2 Number the chain from the double bondCH3─CH─CH=CH─CH penteneSTEP 3 Give the location of each substituent4-methyl- 2-pentene
13 Naming Alkynes with Substituents CH3│Write the IUPAC name for HC≡C─CH─CH3STEP 1 Name the longest carbon chain butyneSTEP 2 Number the chain from the double bond1-butyneSTEP 3 Give the location of each substituent3-methyl-1-butyne
14 Learning Check Write the IUPAC name for each of the following: 1. CH2=CH─CH2─CH32. CH3─CH=CH─CH3CH3|3. CH3─CH=C─CH34. CH3─CC─CH3
15 Solution Write the IUPAC name for each of the following: 1. CH2=CH─CH2─CH butene2. CH3─CH=CH─CH buteneCH3|3. CH3─CH=C─CH methyl-2-butene4. CH3─CC─CH butyne
16 Learning Check Write the structural formula for each of the following: A. 2-pentyneB. 3-methyl-2-pentene
17 Solution Write the structural formula for each of the following: A. CH3─CH2─C≡C─CH pentyneCH3B. CH3─CH2─C=CH─CH3 3-methyl-2-pentene
22 Cis-Trans IsomerismCis-trans isomers do not occur if a carbon atom in the double bond is attached to identical groups.Identical Identical2-bromopropene ,1-dibromoethene(not cis or trans) (not cis or trans)HBrHH
23 Naming Cis-Trans Isomers The prefixes cis or trans are placed in front of the alkene name when there are cis-trans isomers.cis transcis-1,2-dibromoethene trans-1,2-dibromoethene
31 Learning CheckWrite an equation for the hydrogenation of 1-butene using a platinum catalyst.
32 Solution Write an equation for the hydrogenation of 1-butene using a platinum catalyst.PtCH2=CH─CH2─CH3 + H2 CH3─CH2─CH2─CH3
33 Trans Fats In vegetable oils, the unsaturated fats usually contain cis double bonds.During hydrogenation, some cis double bonds are converted to trans double bonds (more stable) causing a change in the fatty acid structureIf a label states “partially” or “fully hydrogenated”, the fats contain trans fatty acids.
34 Learning Check(T) True or (F) FalseA. ____ There are more unsaturated fats in vegetable oils.B. ____ Hydrogenation converts some cis-double bonds totrans- double bonds.C. ____ Animal fats have more unsaturated fats.
35 Solution (1) True or (2) False A. T There are more unsaturated fats in vegetable oils.B. T Hydrogenation of oils converts some cis-doublebonds to trans- double bonds.C. F Animal fats have more unsaturated fats.
36 Learning Check Write the product of each the following reactions: Pt CH3─CH=CH─CH3 + H2+ H2
37 SolutionPtCH3─CH=CH─CH3 + H CH3─CH2─CH2─CH3+ H Pt
38 HalogenationIn halogenation, halogen atoms add to the carbon atoms of a double bond or triple bond.
39 Learning Check Write the product of the following addition reactions: 1. CH3─CH=CH─CH3 + Cl22.
40 Solution Write the product of the following addition reactions: Pt 1. CH3─CH=CH─CH3 + Cl2Cl Cll lCH3─CH─CH─CH32.
42 HydrohalogenationIn hydrohalogenation, the atoms of a hydrogen halide add to the carbon atoms of a double bond or triple bond.
43 Markovnikov’s RuleWhen an unsymmetrical alkene undergoes hydrohalogenation, the H in HX adds to the carbon in the double bond that has the greater number of H atoms .
44 Hydration In the addition reaction called hydration An acid H+ catalyst is required.Water (HOH) adds to a double bond.An H atom bonds to one C in the double bond.An OH bonds to the other C.H OHH │ │CH3─CH=CH─CH3 + H─OH CH3─CH─CH─CH3
45 Hydration When hydration occurs with a double bond that has an unequal number of H atoms,The H atom bonds to the C in the double bond with the most H.The OH bonds to the C in the double bond with the fewest H atoms.OH HH │ │CH3─CH=CH2 + H─OH CH3─CH─CH2(1H) (2H)
46 Learning Check Write the product for the hydration of each of the following:H+1. CH3─CH2─CH=CH─CH2─CH HOHCH3│ H+2. CH3─C=CH─CH2─CH HOHHOH
51 Polymers Polymers are Large, long-chain molecules. Found in nature, including cellulose in plants, starches in food, proteins and DNA in the body.Also synthetic such as polyethylene and polystyrene, Teflon, and nylon.Made up of small repeating units called monomers.Made by reaction of small alkenes.
52 PolymerizationIn polymerization, small repeating units called monomers join to form a long chain polymer.monomer unit repeatsn
65 Aromatic Compounds in Nature and Health Vanillin AspirinIbuprofen Acetaminophen
66 Naming Aromatic Compounds Aromatic compounds are namedWith benzene as the parent chain.With one side group named in front of benzene.methylbenzene chlorobenzene
67 Some Common Names Some substituted benzene rings Have common names used for many years.With a single substituent use a common name or are named as a benzene derivative.toluene aniline phenol(methylbenzene) (benzenamine) (hydroxybenzene)
68 Aromatic Compounds with Two Groups Two naming systems are used when two groups areattached to a benzene ring.Number the ring to give the lowest numbers to the side groups.Use prefixes to show the arrangement:ortho(o-) for 1,2-meta(m-) for 1,3-para(p-) for 1,4-
69 Aromatic Compounds with Two Groups 3-chlorotoluene ,4-dichlorobenzene chlorophenolm-chlorotoluene p-dichlorobenzene o-chlorophenol
70 Learning Check Select the correct name for each compound: 1) chlorocyclohexane2) chlorobenzene3) 1-chlorobenzene1) 1,2-dimethylbenzene2) m-xylene3) 1,3-dimethylbenzene
77 Properties of Aromatic Compounds Have a stable aromatic bonding system.Are resistant to many reactions.Undergo substitution reactions, which retain the stability of the aromatic bonding system.
78 Substitution Reactions In a substitution reaction, a hydrogen atom on a benzene ring is replaced by an atom or group of atoms.Type of substitution H on benzene replaced byHalogenation chlorine or bromine atomNitration nitro group (—NO2)Sulfonation —SO3H group
79 Halogenation In a halogenation An H atom of benzene is replaced by a chlorine or bromine atom.A catalyst such as FeCl3 is needed in chlorination.A catalyst such as FeBr3 is needed in bromination.
80 Nitration In the nitration of benzene An H atom of benzene is replaced by a nitro (-NO2) group from HNO3.An acid catalyst such as H2SO4 is needed.
81 Sulfonation In a sulfonation An H atom on benzene is replaced by a —SO3H group from SO3.An acid catalyst such as H2SO4 is needed.
82 Learning CheckWrite the equation for the bromination of benzene including catalyst.
83 SolutionWrite the equation for the bromination of benzene including catalyst.