1. An Intro to Organic Chemistry
Hydrocarbons
An Intro to Organic Chemistry

2. The Carbonyl Group
A new and important bond is when a carbon is double bonded to an oxygen.
Written several different ways:
C=O H2CO

3. Hybridization
When the orbitals of the atoms overlap and create new orbitals.
They have different shapes and geometries.
It is like adding two math functions together to get a new one.

4. Hybridization Carbons can be hybridized three ways:
sp3 – normal hybridization; four bonding sites around the carbon; Methane
sp2 – hybridization with one double bond; three bonding sites around the carbon; Formaldehyde
sp1 – hybridization with a triple bond; two bonding sites around the carbon; Acetylene

5. Bond Angles Four things around an atom is tetrahedral
Bond angle = 109.5o
Three things around an atom is trigonal planar
Bond Angle = 120o
Two things around an atom is linear
Bond Angle = 180o

6. Naming Organic Compounds
The number of carbons in the chain is the basis for all the naming of organic molecules.
The first four are hard, the next are easy. (they come from the Latin and Greek number roots)

7. Carbon Chain Roots # Carbons Root 1 Meth- (form-) 2 Eth- (acet-)
3 Prop-
4 But-
5 Pent-
6 Hex

8. Carbon Chain Roots (cont’d)
# Carbons Root
7 Hept-
8 Oct-
9 Non-
10 Dec-

9. Putting it all together!
Use the roots as the base for the name and then add “functional groups” that say what else is in the molecule (and where).
It is like a Christmas Tree
1) Choose the tree type (root)
2) Add ornaments (functional groups)
LEARN THE PATTERN…don’t memorize them!

10. Choosing a Backbone The backbone describes the carbon chain.
Classify them using the root based on number of carbons and types of bonds.
There are four groups of backbone chains:
Alkanes
Alkenes
Alkynes
Cyclic

11. Alkanes The carbon chain contains only SINGLE bonds between carbons.
The name ends in “–ane.”
Examples:
CH4 methane
H3C-CH3 ethane
CH3CH2CH2CH3 butane

12. Alkenes
The carbon chain contains at least one DOUBLE bond between carbons.
The name ends in “–ene.”
Examples:
CH2=CHCH3 propene
H2C=CH2 ethene
CH3CH2CH=CH2 butene

13. Alkynes
The carbon chain contains at least one TRIPLE bonds between carbons.
The name ends in “–yne.”
Examples:
HC=CH ethyne (acetylene)
CH3CH2C=CH butyne

14. Cyclic Structures
A aromatic (benzene) ring of alternating single and double bonds
Name is benzene.
Cyclic carbon chains
are named with cyclo-
as a prefix. Example: cyclohexane

15. Structural Isomers
Chemicals that have the same formula but have different backbones.
Example: C4H10

16. More Isomers
Draw the isomers for C5H12

17. Practice
Do problems 30 and 31 on the worksheet.

18. Functional Groups
Once the backbone has been chosen, there are often other atoms substituted on the chain. These are called functional groups.
There are a LOT of functional groups. We will learn the most common ones.

19. Carbon Functional Groups
Sometimes the added part of the molecule is another carbon chain.
We name these the same way as the backbone, but at the end of the word we put –yl.
Example:
The backbone is a butane chain, but a methyl group is substituted on the second carbon:
2-methyl butane

22. The Final Rules
Rule 1: Find the longest chain of continuous carbons to be the backbone.
Rule 2: Number the carbons to give the functional groups the lowest possible number.

23. The Final Rules (cont’d)
Rule 3: Number and name the functional groups.
Rule 4: List functional groups in alphabetical order.
3-ethyl-2,4,5-trimethyl heptane

24. Some examples…
Take a few minutes and do 1, 5, 12, 20, 24, 26, 28 on the worksheet.
Let’s play a game!!

25. Rules of the Game Rule 1: Make teams of three.
Rule 2: All references are allowed.
Rule 3: The team that draws has one minute to put the correct structure or name on the board for 10 points.
Rule 4: If it is incorrect, the other groups can steal 5 points by giving the name or structure of the incorrect molecule.
Rule 5: All-play molecules are denoted with an asterisk and the team that hands me their marker first with the correct answer gets 10 points. Other correct answers get 3 points.