2 Hydrocarbons – organic compounds that contain only atoms of hydrogen and carbon.As the number of carbons in a hydrocarbon increases,its boiling point (bp) increases. This is because biggermolecules attract each other with greater dipole-dipoleforces. This holds them together better in a liquid andmakes it harder to break them apartinto gases.HCbp = Cbp = -89 0Cbp = 36 0C
4 The alkanes are a homologous series of saturated (only single bonds) hydrocarbonsthat release energy when burned.methane CH4ethane C2H6propane C3H8butane C4H4ETC.
5 Each next heavier member of the alkanes is formed by adding a CH2 unit. SeeEx. ethane + CH2 unit propaneGeneral formula for alkanes: CnH2n+2 (see Table Q)n = 1: CnH2n+2 = C1H2•1+2 = C1H4 = CH4 methanen = 2: CnH2n+2 = C2H2•2+2 = C2H ethanen = 3: CnH2n+2 = C3H2•3+2 = C3H propanen = 4: CnH2n+2 = C4H2•4+2 = C4H butaneHC
6 Compounds in which each member differs from the one before it by the same additional unit are calleda homologous series.Ex. What is the molecular formula for the alkane that has 8 carbon atoms?alkane formula: CnH2n+2n = 8: CnH2n+2 = C8H2•8+2 = C8H18Sketch its structuralformula:Ball and stick view:Skeletal view:Note how the actual shaped is bent or kinked.
7 Use Table P to name them.Each alkane is named byadding the prefix to –ane.Ex. What is the name of thealkane of the last example?Ex. What is the name of thealkane that has five C atoms?What is its molecular formula?Sketch its structural formula.octanepentaneC5H12
8 B. The alkenes are a homologous series of unsaturated (not all single bonds) hydrocarbonsthat contain one double bond. There must be at least 2 carbon atoms toform an alkene. The simplest member isethene (also known as ethylene and olefin).ethene:structuralformula:C2H4Other views:
10 Many ethylenes = polyethylene Polyethylene or polythene (IUPAC name polyethene or poly(methylene)) is the most widely used plastic, with an annual production of approximately 80 million metric tons. Its primary use is within packaging (plastic bag, etc.).
12 HDPE is used in products and packaging such as milk jugs, detergent bottles, margarine tubs, garbage containers and water pipes. One third of all toys are manufactured from HDPE. In 2007 the global HDPE consumption reached a volume of more than 30 million tons.[6
13 Next alkene after ethene: propenemolecular formula:C3H6Otherviews:structural formula:How many carbon atoms does it have?3How many double bonds?1
14 The next alkenes are: butene, pentene, etc. Alkenes are named using the same prefixesthat are used for alkanes.The general formula foralkenes is in Table Q:CnH2nEx. What are the name andgeneral formula for the alkenethat has nine carbon atoms?C9H18
15 C. The alkynes are a homologous series of unsaturated (not all single bonds) hydrocarbonsthat contain one triple bond.As with the alkenes, there must be at least 2carbon atoms to form an alkyne. The simplestmember is ethyne (also known as acetylene):molecular formula:structural formula:Other views:C2H2
16 Next alkyne after ethyne: propynemolecular formula:C3H4Otherviews:structuralformula:How many C atoms does it have?3How many double bonds?1
17 The next alkynes are: butyne, pentyne, etc. Alkenes are named using the same prefixesthat are used for alkanes and alkenes.The general formula foralkenes is in Table Q:CnH2n-2Ex. What are the name andgeneral formula for the alkynethat has seven carbon atoms?heptyne
18 Ex. Name and give the molecular formula of the… …alkane with 6 carbon atoms:…alkene with 10 carbon atoms:…alkyne with 5 carbon atoms:Ex. Circle all alkanes, star all alkenes and box allalkynes in the list below. (Some are not possible.)CH4 C3H8 C2H2C5H10 CH2 C3H8C4H10 C6H10 C7H12C20H42 C3H6 C9H20C3H10 C2H4 C8H14hexanedecenepentyne
20 Ex. Name and give the molecular formula of the… …alkane with 6 carbon atoms:…alkene with 10 carbon atoms:…alkyne with 7 carbon atoms:Ex. Circle all alkanes, star all alkenes and box allalkynes in the list below. (Some are not possible.)Mark with an S for saturated and a U for unsaturated.CH4 C3H8 C2H2C5H10 CH2 C3H8C4H10 C6H10 C7H12C20H42 C3H6 C9H20C3H10 C2H4 C8H14hexanedeceneheptyneSSUUUSSUUSUSUU
21 Ex. Put in order of increasing boiling points from left to right:decane, ethane, nonane, pentane,Ex. What are the names of the following?1.2.3.ethane,pentane,nonane,decanebutyneheptanehexene
22 What is this ring ofhydrocarbons, which isproduced in volcanoes,forest fires and cigarettesmoke…?Very useful,very toxic.
23 D. The examples so far are open hydrocarbons. Other types include cyclic hydrocarbons. Twoexamples of these are shown here:structuralskeletalstructuralskeletalcyclo_______ hexanea _________ “ring”benzeneAre the above two compounds alkanes,alkenes or alkynes?cyclohexane is an alkanebenzene is in a class by itself