Introduction to Organic Chemistry

CHEM 2124 – General Chemistry II

Alfred State College

Professor Bensley

Learning Objectives Recognize the characteristic features of

organic compounds. Predict the shape around atoms in organic

molecules. Use shorthand notation to draw organic

molecules. Recognize the common functional groups

and understand their importance.

Learning Objectives Distinguish organic compounds from ionic

inorganic compounds. Determine whether or not an organic

compound is polar or non-polar. Determine solubility properties of organic

compounds.

I. Introduction to Organic Chemistry

Organic chemistry is the study of compounds thatcontain the element carbon.

II. Characteristics of Organic Compounds

1. All organic compounds contain carbon atoms and most contain hydrogen atoms.

2. Carbon forms single, double, and triple bonds toother carbon atoms.

3. Some compounds have chains of atoms and somecompounds have rings.

II. Characteristics of Organic Compounds

4. Organic compounds may also contain elements other than carbon and hydrogen.

THE RULE OF “HONC”

III. Drawing Organic Molecules

A. Condensed Structures

•Some bond lines can be drawn in for effect or to show specific bonding.

III. Drawing Organic Molecules

•Identical groups can be condensed further:

A. Condensed Structures

III. Drawing Organic Molecules

B. Skeletal Structures

IV. Functional Groups

A. Hydrocarbons

•Alkanes•Alkenes•Alkynes•Aromatics

B. Compounds Containing a Single Bond to a Heteroatom

C. Compounds Containing a C=O (Carbonyl) group

V. Properties of Organic Compounds

V. Properties of Organic Compounds

•A covalent bond is nonpolar when two atoms of identical or similar electronegativity are bonded.

A. Polarity

•If the individual polar bonds (dipoles) cancel in a molecule, the molecule is nonpolar.

•If the individual bond dipoles do not cancel, the molecule is polar.

V. Properties of Organic Compounds

•The rule of solubility is “like dissolves like.”

B. Solubility

CH3CH2CH2CH2CH2CH3

hexane•small nonpolar molecule•no O or N present•H2O insoluble•organic solvent soluble

•small polar molecule•O atom present•H2O soluble•organic solvent soluble

CH3CH2—OHethanol

cholesterol

VI. Shapes of Organic Molecules

VSEPR theory: The most stable arrangement keepsthe groups on a central atom as far away from eachother as possible.

VI. Shapes of Organic Molecules

To draw a 3-D tetrahedron in 2-D, we use:

•a solid line for bonds in the plane

•a wedge for a bond in front of the plane

•a dashed line for a bond behind the plane