1. Section 9.3 (pg. 374-380) Naming Organic Compounds: Alkenes and Alkynes Today’s Objectives: 1)Name and draw structural, condensed structural, and line diagrams and formulas for saturated and unsaturated aliphatic (including cyclic Containing up to 10 carbon atoms in the parent chain/cyclic structure Containing only one type of a functional group or multiple bond Using the IUPAC nomenclature guidelines 2)Identify types of compounds from the functional groups, given the structural formula 3)Define structural isomerism and relate to variations in properties

2. Review:  Find and name all of the isomers of pentane (C 5 H 12(l) )

3. Structural Isomerism  Compound with the same molecular formula but different structures  They will have different chemical and physical properties – based on their different structures

4. Alkenes and Alkynes  Alkenes – hydrocarbons containing a double C-C bond  General formula (C n H 2n ) - (like cycloalkanes)  Alkynes – hydrocarbons containing a triple C-C bond  General formula (C n H 2n-2 ) – (like cycloalkenes)  Alkenes and Alkynes are considered unsaturated compounds. They do not have the maximum number of hydrogen atoms surrounding each carbon.  Reactivity: Alkynes (highest), Alkenes, Alkanes (lowest)

5. Naming Alkenes and Alkynes 1. Find the parent chain. It MUST contain the multiple bond.  If the bond is a double, the suffix for the parent chain will be -ene  If the bond is a triple, the suffix for the parent chain will be –yne 2. Count carbon atoms so that the multiple bond will be on the lowest possible number. Indicate the number that the multiple bond falls on directly before the suffix 3. Name branches as before

6. Naming Alkenes and Alkynes  Draw the following as condensed structural formulas: 4-methylpent-2-yne methylpropene (why don’t we need a number?)

7. Naming Alkenes and Alkynes  Name the following: 3-methylbut-1-ene 5-methylhex-2-ene

8. Naming Alkenes and Alkynes 4. It is possible for a molecule to have more than one double bond. These are called alkadienes and have the same general formula as alkynes (C n H 2n-2 )  If this is the case, indicate both numbers where the double bond is formed, and change the suffix to –diene. a) Draw buta-1,3-diene: b) What is the IUPAC name for the following: buta-1,2-diene

9. Cycloalkenes and -ynes  The rules for naming cycloalkenes and cycloalkynes are the same as naming cycloalkanes  The numbering for the carbon atoms begins with the double bond; the carbons of the double bond are carbons 1 and 2; lowest numbers possible  Draw 3-methylcyclohexene as a condensed structural formula

10. Today’s homework  Pg. 377 #1-5  Pg. 380 #6 (a-b), 7 (a-b), 11 (a-b)  Due wednesday /22 pts  What is coming up Wednesday?  Naming Aromatics  Boiling point and Chemical Properties Analysis