1. Hydrocarbons
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2. Hydrocarbons…
Are composed of Hydrogen and Carbon
Simplest form of Hydrocarbons are Alkanes
Alkanes can exist in the form of a straight chain or a branched chain
were originally thought to have only been created by living organisms

3. The 1st 10 Straight – Chain Alkanes
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The 1st 10 Straight – Chain Alkanes

4. Thornburg 2016
Skeletal Formulas
A common shorthand way to draw organic molecules is to use their skeletal formulas
Only carbon atoms and functional groups are shown in a skeletal formula
A skeletal formula uses lines to represent bonds between carbon atoms.
Even though the hydrogen atoms are not drawn in the skeletal diagram, it is understood that the hydrogens are still there

5. Drawing Skeletal Formulas
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Drawing Skeletal Formulas
Draw the skeletal formula for these 2 molecules:

6. Thornburg 2016
Name these alkanes
hexane
heptane
butane
propane

7. Drawing Hydrocarbons Draw Lewis Dot Structures for the following:
Ethane Pentane
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8. Branched Chain Alkanes
An alkyl group is a short side chain called a substituent that branches off from the parent chain of a hydrocarbon
The alkyl group is named using the same prefixes as are used in naming the parent chain
Example:
2 – methylpropane
Thornburg 2016

9. Name these alkanes Thornburg 2016 3 - methylhexane
2,3 - dimethyl butane
2, 2 - dimethylpentane
3, 5 - dimethylheptane
4 – ethyl, 3,6 – dimethyloctane

10. IUPAC Rules
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Find the longest carbon chain. This is the parent structure and will provide the root for the name of the molecule
Number the carbon atoms. Start from the end that will give substituent chains and double bonds smaller numbers.
Add numbers to show where double or triple bonds start within the parent chain.
Add numbers to the substituent groups (ex: 3- methyl, 5 – ethyl)
If a substituent shows up more than once, use prefixes to indicate this
Put alkyl substituents in alphabetical order. Ignore prefixes
Use proper punctuation. Commas separate numbers, dashes separate words. No spaces between names

11. Thornburg 2016
Functional Groups
Functional Group: A functional group is anything that is added to a carbon chain (or carbon ring) that changes it chemically.
This can be:
Another carbon chain.
A halogen gas atom.
An alcohol group.
A ketone.
Etc.
There are over 1000 functional groups. You will be expected to be familiar with 8 of these.

12. Common Functional Groups

13. Thornburg 2016
Alkenes
Alkenes are hydrocarbon chains that have a double bond in their structure
Examples:
When naming alkenes, we identify the location of the double bond by using numbers

14. Practice with Alkenes Name these alkenes: Thornburg 2016 1 - pentene
2 – methyl – 1 – butene

15. Thornburg 2016
Alkynes
Alkynes are hydrocabon chains that have a triple bond in their structure
When naming alkynes, we identify the location of the triple bond by using numbers

16. Practice with Alkenes
Name these alkynes:
pentyne
4 – octyne