Organic ChemistryIn chemistry the word “organic” has a different meaning than in the grocery store. Organic chemistry is the study of ______________________________________________.Almost everything around you is made up of carbon, so this is a big topic. We are made of carbon, and so are things like lighter fuel and plastic bags. Depending on how the carbon is bonded and what it is bonded to it can create materials with very different properties.

Bonding of Carbon AtomsWhat’s so special about carbon anyway? It tends to form ____________ bonds with other carbon atoms to form chains. Because carbon has ___ valence electrons it can form ___ bonds.

When 1 pair of electrons is shared between two carbon atoms the bond is called a __________ covalent bond.

If carbon atoms share two pairs of electrons the bond is called a _________ covalent bond.

Carbons can even share three pairs of electrons. This bond is called a _________ covalent bond.

Saturated =

Unsaturated =

Chains of carbon atoms can be open or closed, or even form three-dimensional networks.

C

Hydrocarbons –

Homologous series =

As members of a homologous series increase in molecular mass (the number of carbons increases), their boiling and melting points ___________.

Hydrocarbons are named according to their number of carbons and the type of bonds in them. Tables P and Q are used together for this purpose.

Alkanes:

Alkenes:

Alkynes:

Name the following hydrocarbons from their descriptions:1. 9 carbons with only single bonds = _____________2. 5 carbons with a double bond = _____________3. 7 carbons with only single bonds = _____________4. 5 carbons with a triple bond = _____________5. 6 carbons with a double bond = _____________

Each homologous series has a general formula that you can follow to determine the number of hydrogens attached to a molecule.

Alkanes = Alkenes = Alkynes =

Where n = _____________________________

Alkane

Ex) Methane n = ____, and the formula _______ is used, so methane = C H

Practice this by writing out the formulas of the hydrocarbons in the previous examples.

There are many ways that the makeup of a molecule can be expressed. Methane Ethane

Molecular Formula

Structural Formula

Condensed Formula

Ball-and-Stick Model

Space-Filling Model

Drawing Structural Formulas of HydrocarbonsAlkanes1. Determine the number of carbons and

draw that many in a row2. Because the molecule name ends in –ane

you know that there are only single bonds. Connect all of the carbons with a single line.

3. Each carbon atom must have 4 bonds connected to it. Add enough hydrogens so that each carbon has 4 total bonds connected to it.

1 Carbon

Example: Pentane

4. Use the molecular formula to make sure that you have the correct number of hydrogens.

Draw the structural formula for propane:

Alkenes1. Determine the number of carbons and

draw that many in a row connected by a single line.

2. Because the molecule name ends in –ene you know that there is a double bond. The name of the molecule will tell you where that bond is located. For example, 2-butene will tell you that there are 4 carbons and the double bond is located after the second one. Add another line for the double bond.

3. Each carbon atom must have 4 bonds connected to it. Add enough hydrogens so that each carbon has 4 total bonds connected to it.

4. Use the molecular formula to make sure that you have the correct number of hydrogens.

Draw the structural formula for 4-hexene:

Alkynes follow the same rules as alkenes, except there is a triple bond, not a double bond.

Draw the structural formula for 2-butyne:

Example: 3-Pentene

19. Write the molecular formula for 1-octene and draw its structural formula:

20. Write the molecular formula for 3-pentyne and draw its structural formula:

Isomers –

As the number of carbon atoms increases, the number of possible isomers _____________.The letter n before the name of a hydrocarbon signifies that it is the ___________, or straight chain isomer. Branched isomers must have different names.

Naming IsomersThe rules for naming organic compounds are governed by the International Union of Pure and Applied Chemistry (IUPAC).

Naming Procedure: Example1. Find the longest continuous chain of carbons and use its name as the base. (Example: 4 carbons = butane)

2. Count the number of carbons in the side branch and assign a prefix based on the name of the corresponding alkane. (Example: 1 carbon = methane = methyl)

3. If necessary, the location of the side branch (alkyl group) is shown by assigning numbers to the carbons in the longest chain. Numbering should begin at the end that has the side chain attached to the lowest number possible. (Example: 2-methylbutane, not 3-methyl butane)

4. If more than 1 side branch is attached commas are used to separate the numbers in the name and prefixes are used to denote more than one of the same group, such as 2,2-dimethylbutane:

Isomer Naming Practice

Name the following molecules:

C - C - C - C|      C     

C - C - C - C|      C      -butane

C - C - C - C|      C     

methylbutaneC1 - C2 - C3 - C4

|       C      

2-methylbutane

Alkane Alkyl GroupMethane MethylEthane EthylPropane Propyl

Example: = 2,2,4-trimethyl pentane

Draw the following molecules:5. 2-ethyl, 3-methylbutane 6. 3,3-dipropylpentane