Organic Chemistry The study of carbon based compounds with some

exceptions. The exceptions are carbides, carbonates and oxides.

Why is the carbon atom unique? Carbon is unique

It has 4 electrons in its outer shell. It has room for 4 bonds to 4 other atoms. These bonds can be single, double, or triple.

Hydrocarbons

The largest group of organic compounds are known as

hydrocarbons. These compounds contain hydrogen and carbon. Most of

these compounds are derived from petroleum.

Petroleum Petroleum is a mixture of alkanes, cycloalkanes,

and aromatic hydrocarbons. Petroleum is formed from the slow decomposition of

buried marine life, primarily plankton and algae.

As petroleum is formed it is forced through porous rock until it reaches an impervious layer of rock. Here it forms an accumulation of petroleum and

saturates the porous rock creating an oil field.

Refinery and tank storage facilities, like this one in Texas, are needed to change the hydrocarbons of crude oil to many different petroleum products.

Hydrocarbons Hydrocarbons exist in three general

shapes. Aliphatic- in chains

Hydrocarbons Cyclic- in rings

Hydrocarbons Aromatic – contain the benzene ring. They

usually have distinctive odors.

Hydrocarbons Hydrocarbons are also distinguished by the

type of bonds they contain between the carbon atoms.

Hydrocarbons based on bond type Alkanes – contain only single covalent

bonds between carbon atoms. Alkenes – contain at least one double bond

between carbon atoms. Alkynes – contain at least one triple bond

between carbon atoms.

Alkanes, Alkenes, and Alkynes

Carbon requires an octet. Carbon must have 4 bonds around it.

Alkane Nomenclature When writing the names for alkanes,

prefixes must be known. The prefixes identify the number of carbon atoms in the compound.

1 methane CH4

2 ethane C2H6

3 propane C3H8

4 butane C4H10

Alkane Nomenclature 5 pentane C5H12

6 hexane C6H14

7 heptane C7H16

8 octane C8H18

9 nonane C9H20

10 decane C10H22

Alkane Nomenclature When writing formulas for the alkanes we

use the formula CnH2n + 2

n represents the number of carbon atoms Example: methane contains 1 carbon atom. C1H2 X 1 + 2 CH4

Without looking back at the prefixes write the molecular and structural formulas for ethane – butane.

Alkane practice 2 ethane C2H6

3 propane C3H8

4 butane C4H10

Using the condensed method In the condensed form of a structural formula,

carbon atoms are still written separately. However, the hydrogen atoms that are attached to a carbon atom are grouped with that carbon atom.

Example: pentane C5H12

H3C-CH2-CH2-CH2-CH3

Write the molecular, traditional structural, and condensed structural formulas for octane.

Alkenes Alkenes must contain at least one double

bond. They take the general form of CnH2n.

The first Alkene is ethene. C2H4

Write the molecular formula and the structural formula for propene.

Alkenes that contain more than 3 carbon atoms When writing the names for alkenes that

contain more than 3 carbon atoms the location of the double bond must be included.

Example: Butene can be 1-butene or 2-butene. C4H8

H2C=CH-CH2-CH3 1-butene H3C-CH=CH-CH3 2-butene

Determining the location of the double bond

Carbon atoms are numbered by starting with the carbon atom closest to the double bond. The numbering can start from either side.

H2C=CH-CH2-CH3 1-butene

1 2 3 4

Determining the location of the double bond

H3C-CH2-CH=CH2 1-butene C4H8

4 3 2 1 Write molecular and structural formulas for

1-pentene

2-pentene

3-hexene

Alkynes Alkynes must contain at least one triple

covalent bond. They take the general form of CnH2n-2. The first alkyne is ethyne.

Ethyne C2H2 is also known as acetylene, which is used as the gas for welding.

Alkynes Alkynes use the same nomenclature as the

Alkenes. After propyne the location of the triple bond must be identified.

Write molecular and structural formulas for propyne, 2-butyne, 1-pentyne, and 3-heptyne.

Review of part I of an introduction to Organic chemistry Write molecular and structural formulas for the

following (you may use the traditional or condensed structural formulas).

1. Methane2. Propane3. Ethene4. 1-Butene5. 2-Hexene6. 3-Octene7. Ethyne8. 2-Heptyne9. 3-Octyne

Hydrocarbon Radicals If one of the hydrogen atoms together with

its associated electron is removed from a hydrocarbon molecule a radical is formed.

Examples: Methane CH4 becomes Methyl CH3

Ethane C2H6 becomes Ethyl C2H5

Propane C3H8 becomes_______________

Functional Groups A group of atoms that give characteristics

and properties to organic compounds. These functional groups may be aldehydes, alcohols, ethers, ketones, amino acids, amides, and others. We will study the alcohols because of their wide use in combustion reactions.

Alcohols Alcohols contain the hydroxyl group OH. Unlike the

hydroxide ion the hydroxyl group does not contain an electrical charge.

Simple alcohols take the general form R - OH. The R represents a hydrocarbon radical. Symbol R An atom or a group of atoms with at least one

unpaired electron.

Example: If the radical is methyl (CH3), the alcohol becomes CH3OH which is known as methyl

alcohol or methanol. Write the molecular formulas for propyl alcohol and

butanol.

Saturated and Unsaturated Hydrocarbons

Saturated hydrocarbons contain the maximum number of hydrogen atoms around each carbon atom. They contain only single covalent bonds between carbon atoms, therefore they are usually alkanes.

Unsaturated hydrocarbons are just the opposite and they contain double or triple bonds between carbon atoms. They are usually alkenes and alkynes.

Key terms from part II.

1. Hydrocarbon radical

2. Functional group

3. Alcohol

4. Saturated hydrocarbon

5. Unsaturated hydrocarbon

Inorganic and Organic nomenclature practice Write the missing name or molecular formula for the following.1. Sulfur dioxide2. Carbon dioxide3. Phosphorus pentachloride4. Dinitrogen tetroxide5. Sulfur trioxide6. H3C-CH2-OH7. H3C-CH2-CH2-CH3

8. H3C-CH=CH-CH2-CH3

9. 2-Hexyne10. Butyl alcohol11. Methanol12. Hydrosulfuric acid13. Sulfuric acid14. Sulfurous acid15. Hypochlorous acid

Inorganic and Organic nomenclature practice1. Oxygen difluoride2. Hydrochloric acid3. Ethyne4. 2-Hexene5. Propyl alcohol6. HCN(aq)

7. ethene8. HNO2(aq)

9. Carbonic acid10. Acetic acid11. Carbon tetrachloride12. Propane13. Propene14. propyne