Organic Chemistry Chemistry of Carbon

Objectives To define what constitutes an “organic compound” To describe why organic compounds are important and give some examples of them To be able to name simple unbranched organic compounds with single bonds To identify and draw isomers of organic molecules To be able to name more complex, branching organic compounds with single bonds

What are Organic Compounds? Carbon containing molecules Many organic molecules are made by living things, but not all

Examples of Organic Compounds Hydrocarbons Molecules composed entirely of Carbon and Hydrogen Methane, Propane, Benzene, Octane, Ethylene (Ethyne), Acetylene (Ethyne) Fossil fuels...

Examples of Organic Compounds Lipids Fats, waxes, sterols, fat soluble vitamins, triglycerides, diglycerides, etc. Store energy in body, form cell membranes, hormones...

Examples of Organic Compounds Carbohydrates Carbon, Hydrogen and Oxygen in specific ratios Sugars, starches, cellulose, chitin

Examples of Organic Compounds Polymers (large molecules of repeating structural units) Proteins and Nucleic Acids Vinyl, nylon, plastics...

Alkanes Simple, saturated hydrocarbons (all single bonds) Each carbon bonded to four atoms tetrahedral geometry around carbons

Naming Alkanes C atoms Word RootNameStructureFormula 1Meth-MethaneCH 4 2Eth-EthaneCH 3 -CH 3 C2H6C2H6 3Prop-PropaneCH 3 -CH 2 -CH 3 C3H8C3H8 4But-ButaneCH 3 -(CH 2 ) 2 -CH 3 C 4 H 10 5Pent-PentaneCH 3 -(CH 2 ) 3 -CH 3 C 5 H 12 6Hex-HexaneCH 3 -(CH 2 ) 4 -CH 3 C 6 H 14 7Hept-HeptaneCH 3 -(CH 2 ) 5 -CH 3 C 7 H 16 8Oct-OctaneCH 3 -(CH 2 ) 6 -CH 3 C 8 H 18 9Non-NonaneCH 3 -(CH 2 ) 7 -CH 3 C 9 H 20 10Dec-DecaneCH 3 -(CH 2 ) 8 -CH 3 C 10 H 22

Try naming these molecules CH 3 - CH 2 - CH 2 - CH 2 - CH 2 - CH 3 Hexane CH 3 - CH 3 Ethane CH 3 - CH 2 - CH 3 Propane

Alkanes can be BRANCHED Butane C 4 H 10 n-butane (normal butane), is unbranched, C 4 H 10 isobutane (an isomer of n-butane) is branched, C 4 H 10 isomerism = two molecules have same atoms but different bonds

Alkanes can be BRANCHED Pentane C 5 H 12 n-pentane (normal pentane), is unbranched, C 5 H 12 We can make isomers of n-pentane, with branches, but still C 5 H 12 Can you think of another isomer of pentane?

Draw three structural isomers of heptane

Naming Branched Alkanes Step 1: Find longest continuous chain of carbons. In this case, you have a chain of 8 - so primary name of molecule is Octane

Naming Branched Alkanes Redrawn to show longest chain (8 carbons) STEP 2 - Count from beginning of longest chain to carbon where branch occurs (in this case, count 4 carbons, not 5)

Naming Branched Alkanes STEP 3 - Count the carbons on the branch In this case, there are 2 carbons on the branch The branch is called a substituent There are rules for naming substituents based on # of Cs in them

Naming Branched Alkanes STEP 4 - Name the substituent 1 carbon = methyl 2 carbons = ethyl 3 carbons = propyl In this case, our substituent is called ethyl because it has 2 carbons

Naming Branched Alkanes STEP 5 - Name the molecule since our substituent is on the 4th Carbon We call this molecule 4- ethyloctane

What if there is more than one branch? 3, 4 - diethyloctane

What if there is more than one branch? 3, 4, 5 - trimethyloctane

Naming Branched Alkanes 6-ethyl-2-methyl-octane list substituents in alphabetical order

Name this molecule 5-ethyl-3-methyl- heptane 3-ethyl-5-methyl- heptane is equally correct remember to list substituents in alphabetical order

Name this molecule (this is hard!) 3-ethyl-2,2,3-trimethyl- heptane

Practice Time! Work on 2 worksheets Check key (with me) Finish as homework (I will scan key and put on website)