1. Chapter 8 Chemical Reactions
8.4 Functional Groups and Reactions of Organic Compounds
Learning Goal Classify organic molecules according to their functional groups; draw the condensed structural formulas for products of reactions of organic compounds.
The propane from the torch undergoes combustion, which provides energy to solder metals.
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2. Organic Reactions, Combustion
The most common type of reaction that organic compounds undergo is combustion.
Hydrocarbons are carbon-hydrogen compounds
used as fuels; gasoline is a mixture of different hydrocarbons
burned in the presence of oxygen to produce carbon dioxide, CO2, water, and energy

3. Combustion of Alkanes
Propane, a hydrocarbon with three carbon atoms, is used as fuel in portable heaters and barbeques.
The balanced reaction for combustion of propane, C3H8, is

4. Covalent Bonds in Organic Compounds

5. Functional Groups
Organic compounds are organized according to their functional groups, specific groups of atoms that undergo characteristic chemical reactions.
Compounds with the same functional group have similar chemical properties.

6. Functional Groups, Alkenes
Organic compounds that contain carbon-carbon double bonds are called alkenes.
The simplest alkene contains two carbons:
ethene,
In ethene, each carbon is attached to
a double bond
two hydrogen atoms, with single bonds

7. Functional Groups, Alkenes
Ethene is a plant hormone that promotes the ripening of fruit such as bananas and avocados.
Fruit that is picked early is ripened by exposure to ethene.

8. Chemistry Link to the Environment
Many insects emit very small quantities of chemicals called pheromones to send messages to other members of the same species.
Pheromones can be used
as a signal of danger
to mark a trail
to attract members of the opposite sex

9. Chemistry Link to the Environment
One such communication chemical is called bombykol, emitted by female silkworm moths.
Bombykol
attracts male silkworm moths
contains two double bonds and an alcohol group
can be made by scientists and used as a nontoxic pesticide

10. Chemistry Link to the Environment
Bombykol attracts male silkworm moths.

11. Hydrogenation of Alkenes
Alkenes undergo
addition reactions, where atoms are added to each side of the double bond
hydrogenation reactions, where hydrogen atoms are added to each side of the double bond, turning the alkene into an alkane

12. Hydrogenation of Alkenes
Hydrogenation reactions require a catalyst such as platinum (Pt), nickel (Ni), or palladium (Pd) to speed up the reaction.

13. Functional Groups, Aromatic Compounds
In 1825, Michael Faraday isolated benzene, a hydrocarbon with the formula C6H6.
Because molecules that contain benzene often have fragrant odors, they are called aromatic compounds.
Benzene is a six-carbon ring with alternating single and double bonds.

14. Functional Groups, Aromatic Compounds
Benzene molecules are often represented by a hexagon with a circle in the center.
One example of an aromatic compound, thymol, is found in thyme.

15. Functional Groups, Alcohols
In an alcohol, a hydroxyl (—OH) group replaces a hydrogen in a hydrocarbon.
Ethanol
has the formula
has been known since prehistoric times as an intoxicating product

16. Functional Groups, Alcohols
Ethanol (ethyl alcohol), CH3CH2OH, is formed by the fermentation of grains, sugars, and starches.
Ethanol is used as a solvent for perfumes, varnishes, and some medicines, such as tincture of iodine.

17. Combustion of Alcohols
Alcohols burn with oxygen to produce carbon dioxide and water.
Desserts may be prepared
by pouring liquor on
fruit or ice cream and
lighting it.
A flaming dessert is prepared using a liquor containing ethanol that undergoes combustion.

18. Functional Groups, Aldehydes, and Ketones
Aldehydes and ketones contain a carbonyl group (C O), which is a carbon atom attached to an oxygen atom with a double bond.
In an aldehyde, the carbon atom of the
carbonyl group is also bonded to a
hydrogen atom.
In a ketone, the carbon atom of the
carbonyl group is bonded to two
other carbon atoms.

19. Functional Groups, Aldehydes, and Ketones
Aldehydes and ketones are often found in food flavorings such as vanilla, cinnamon, and spearmint.
Formaldehyde, the simplest aldehyde, is a colorless gas with a pungent odor, used as a germicide and as a way to preserve biological specimens.

20. Functional Groups, Aldehydes, and Ketones
The simplest ketone, known as acetone or propanone, is a liquid with a mild odor. It is widely used as a solvent in cleaning fluids, paint, and nail polish removers.
In the body, acetone may be produced in uncontrollable diabetes, fasting, and with high- protein diets when large amounts of fats are metabolized for energy.

21. Functional Groups, Carboxylic Acids
In a carboxylic acid, the functional group is the carboxyl group, which is a combination of the carbonyl and hydroxyl groups.

22. Functional Groups, Carboxylic Acids
The functional group in the formula for a carboxylic acid can be drawn as follows:
Acetic acid, CH3−−COOH, and water form a solution called vinegar, used in food preparation.

23. Functional Groups, Esters
Esters are similar to carboxylic acids, except the hydrogen atom attached to the oxygen is replaced by a carbon atom.
The functional group in an ester can be drawn as follows:
or CH3—COO—CH3

24. Functional Groups, Esters
Many fragrances found in perfumes and flowers are due to esters.
Esters are also responsible for the odor and flavorings in oranges, bananas, pears, pineapples, and strawberries.
Esters such as ethyl butanoate provide the odor and flavor of many fruits such as pineapples.

25. Chemistry Link to Health
In the 1800s, chemists discovered that salicin, found in willow tree bark, was responsible for the relief of pain.
When ingested, the body converts salicin to salicylic acid, which irritates the stomach lining.
The discovery of salicin in the leaves and bark of the willow tree led to the development of aspirin.

26. Chemistry Link to Health
In 1899, the Bayer Chemical Company produced an ester of salicylic acid called acetylsalicylic acid (aspirin), which is less irritating to the stomach.

27. Functional Groups, Amines
Amines are derivatives of ammonia, NH3, in which the nitrogen atom is attached to one, two, or three carbon atoms.

28. Functional Groups, Amines
Amines are responsible for fish odor. As the proteins in fish decay, they produce putrescine and cadaverine, which have a particularly pungent and offensive odor.

29. Functional Groups, Amides
In an amide, the hydroxyl group of a carboxylic acid is replaced by a nitrogen group.
Compounds that contain amides are used to reduce fever and relieve pain.

30. Classes of Organic Compounds

31. Classes of Organic Compounds

32. Learning Check
Classify each of the following as alcohol, alkene, aldehyde, ketone, carboxylic acid, ester, amide, or amine:

33. Solution
Classify each of the following as alcohol, alkene, aldehyde, ketone, carboxylic acid, ester, amide, or amine: