Alkanes C H n 2n+2 all C are sp3 hybridized  bonds n root suffix formula 3 prop ane C3H8 4 but ane C4H10 5 pent ane C5H12 6 hex ane C6H14 7 hept ane C7H16 8 oct ane C8H18 9 non ane C9H20 10 dec ane C10H22 1 meth ane C H 4 2 eth ane C2H6

Alkanes n = 1-4 gases n = 5-15 liquids n > 15 solids compound m.w. b.p.(Co) CH4 16 -164 C2H6 30 -88.6 C3H8 44 -42.1 C4H10 58 -0.5 C5H12 72 +36.0 n = 1-4 gases n = 5-15 liquids n > 15 solids

Alkanes IMF = q1q2 n = 1-4 gases r n = 5-15 liquids n > 15 solids ____ r n = 5-15 liquids n > 15 solids q  # electrons instantaneous dipole moments - + + -

Alkanes IMF = q1q2 r 72 36.1 72 27.9 72 9.5 structural isomers ____ compound m.w. b.p. 72 36.1 72 27.9 72 9.5 structural isomers same formula different shape r  branching

Reactions of Alkanes combustion __ C3H8 + __ O2  5 __ CO2 + 3 __ H2O 4 exothermic reaction combustion with insufficient O2 __ C3H8 + __ O2  __ CO + __ H2O 3 4 7/2 improperly vented spaces and cigarettes

Reactions of Alkanes Substitution of halogens Cl2  2Cl. step 1 initiation step 2 Cl.+ CH4  CH3. + HCl propagation step 3 CH3.+ Cl2  CH3Cl + Cl. propagation step 4 Cl.+ Cl.  Cl2 termination get a mixture of chlorinated methanes

Halogenation of Alkanes CH3Cl chloro methane methyl chloride CH2Cl2 di chloromethane methylene chloride CHCl3 tri chloromethane chloroform CCl4 tetra chloromethane carbon tetrachloride all liquids at room temperature methane is gas e- rich Cl increases LDF

Nomenclature 1. Pick longest C chain as parent 2. Number C beginning at end with first branch 3. Identify branching substituents Assign each a number 4. Use commas to separate numbers hyphens to separate numbers from names 5. Alphabetize substituents

Nomenclature Structural isomers of C5H12 I. III. II. I. pentane II. 2- 4 1 3 2 1 2 2 3 3 4 4 II. 1 1 2 3 I. pentane II. 2- methyl butane III. 2,2- di methyl propane

Nomenclature R = “alkyl” group 1o 3o primary carbon tertiary carbon 4o secondary carbon quaternary carbon

Nomenclature “common” names to learn: iso propyl alphabetized as i sec- butyl alphabetized as b iso butyl alphabetized as i tert- butyl alphabetized as b