Chapter 20: Organic Chemistry
20.3: Functional Groups
- Functional Group
- A specific group of atoms within a molecule that determines the molecule's chemical properties and reactivity.
- Alcohol
- A compound containing a hydroxyl group (-OH) attached to a carbon atom.
- Carboxylic Acid
- A compound containing a carboxyl group (-COOH), which acts as a weak acid.
- Ester
- A compound derived from carboxylic acids, containing the functional group (-COOR), where R is a hydrocarbon chain.
- Amine
- A compound containing an amino group (-NH₂), which can act as a base.
- Ketone
- A compound with a carbonyl group (C=O) attached to two hydrocarbon groups.
- Aldehyde
- A compound with a carbonyl group (C=O) attached to at least one hydrogen atom.
Examples of Functional Groups
- Hydroxyl (-OH): Found in alcohols (e.g., ethanol).
- Carboxyl (-COOH): Found in carboxylic acids (e.g., acetic acid).
- Amino (-NH₂): Found in amines and amino acids.
- Carbonyl (C=O): Found in ketones and aldehydes (e.g., acetone, formaldehyde).
- Ester (-COOR): Found in esters (e.g., methyl acetate).
Properties of Functional Groups
- Determine the reactivity and solubility of organic compounds.
- Most functional groups are polar and increase water solubility.
- Specific functional groups interact in predictable ways during chemical reactions.
Applications of Functional Groups
- Alcohols are used in disinfectants, solvents, and fuels.
- Carboxylic acids are used in food preservatives and pharmaceuticals.
- Amines are found in proteins and dyes.
- Ketones and aldehydes are used in perfumes and as solvents.
Questions for Students
- What is a functional group, and why is it important in organic chemistry?
- Define the following functional groups: hydroxyl, carboxyl, amino, and carbonyl.
- Explain how functional groups affect the physical and chemical properties of a compound.
- Give an example of a compound with each functional group and describe its use.
- How do functional groups determine the solubility of organic compounds?