Chapter 21 : Organic Chemistry Organic chemistry: Organic chemistry: The study of the compounds of carbon. 85% of all known compounds are organic. Carbohydrates, lipids, proteins, enzymes, nucleic acids, hormones, vitamins, and almost all other chemicals in living systems are organic compounds. < Abundance of the elements in the Earth’s crust.

Chapter 21 : Organic Chemistry Why is organic chemistry a separate discipline within chemistry? Organic Inorganic Vitalism: Vitalism: a “vital force” present in living organisms was believed to be necessary to produce an organic compound. The experiment of Wöhler in 1828 was the first in a series of experiments that led to the demise of the vital force theory. See reaction below:

Chapter 21 : Organic Chemistry Structural formula: Structural formula: Shows the atoms present in a molecule as well as the bonds that connect them. VSEPR model: VSEPR model: The most common bond angles are 109.5°, 120°, and 180°. 180° 120° 109.5° B C NOF H

Chapter 21 : Organic Chemistry Hydrocarbon: Hydrocarbon: A compound composed only of carbon and hydrogen. AlkanesAlkenesAlkynes Arenes (Aromatics)

Chapter 21 : Organic Chemistry Alkanes: Alkanes: Hydrocarbons that contain only carbon-carbon single bonds. The first 10 alkanes with unbranched chains:

Chapter 21 : Organic Chemistry Line-angle formula Line-angle formula: 1.A line represents a single bond. 2.A vertex and a line terminus represent a carbon atom. 3.Hydrogen atoms are not shown in line-angle formulas.

Chapter 21 : Organic Chemistry Alkyl group: A substituent group derived from an alkane by removal of a hydrogen atom. Commonly represented by the symbol R-. Commonly represented by the symbol R-. Named by dropping the -ane from the name of the parent alkane and adding the suffix -yl. Named by dropping the -ane from the name of the parent alkane and adding the suffix -yl.

Chapter 21 : Organic Chemistry IUPAC, How to name alkanes: ane. 1. The name for an alkane with an unbranched chain of carbon atoms consists of a prefix showing the number of carbon atoms and the ending -ane. 2. For branched-chain alkanes, the longest chain of carbon atoms is the parent chain and its name is the root name. 3. Name and number each substituent on the parent chain and use a hyphen to connect the number to the name. 4.Number the parent chain from the end that gives the lower number to the substituent encountered first. 5.Indicate the number of times the substituent occurs by a prefix di-, tri-, tetra-, penta-, hexa-, and so forth. 6.Use a comma to separate position numbers. 7. Alphabetize the names of substituents first, and then insert these prefixes 8.Do not include the prefixes di-, tri-, tetra- in alphabetizing. IUPAC = International Union of Pure and Applied Chemistry

Chapter 21 : Organic Chemistry Cyclic hydrocarbon: A hydrocarbon that contains carbon atoms joined to form a ring. Cycloalkane: A cyclic hydrocarbon in which all carbons of the ring are saturated (has only carbon-carbon single bonds). Cycloalkanes with ring sizes of from 3 to over 30 carbon atoms are found in nature. Five-membered (cyclopentane) and six-membered (cyclohexane) rings are especially abundant in nature.

Physical properties: 1. Non-polar (they dissolve in other non-polar solvents!) 2. Melting/Boiling points and Density:

Chapter 21 : Organic Chemistry Natural gas 90 to 95 percent methane. 5 to 10 percent ethane, and A mixture of other relatively low-boiling alkanes. Petroleum A thick, viscous liquid mixture of thousands of compounds, most of them hydrocarbons formed from the decomposition of marine plants and animals.

Chapter 21 : Organic Chemistry An alcohol may be primary (1°), secondary (2°), or tertiary (3°). Example: C 3 H 8 O

Chapter 21 : Organic Chemistry Example: C 3 H 9 N

Chapter 21 : Organic Chemistry Example: C 4 H 8 O

Chapter 21 : Organic Chemistry Example: C 3 H 6 O 2

Chapter 21 : Organic Chemistry Example: C 3 H 6 O 2