AP Chemistry Unit 3: Intermolecular Forces, Organic Chemistry, and Spectroscopy

Vocabulary flashcards covering intermolecular forces, physical properties, separation techniques, organic nomenclature and functional groups, isomerism, and spectroscopy methods.

Intermolecular Forces (IMFs)

Attractive forces that exist between molecules or particles, whose type and strength depend directly on structural features, polarity, electron distribution, and bonding.

London Dispersion Forces (LDFs)

Attractive forces present in all atoms and molecules, caused by temporary, instantaneous dipoles formed by electron movement that induce dipoles in neighboring species.

Polarizability

The ease with which an electron cloud can be distorted; larger molecules with greater molar masses have larger, more diffuse electron clouds that are more polarizable, leading to stronger dispersion forces.

Dipole-Dipole Interactions

Electrostatic attractions occurring exclusively between polar molecules possessing permanent dipole moments, acting between the partial positive end of one molecule and the partial negative end of an adjacent molecule.

Hydrogen Bonding

A strong, specialized dipole-dipole attraction occurring when hydrogen is directly bonded to fluorine, oxygen, or nitrogen, interacting with lone pairs on adjacent F, O, or N atoms.

Ion-Ion Interactions

Direct electrostatic attractions in an ionic lattice between full positive cations and full negative anions, defined by Coulomb's Law ($F \propto \frac{q_1 q_2}{r^2}$).

Covalent Network Solid

A continuous solid structure, such as $\text{SiO}_2$, where atoms are bound throughout a 3D lattice by strong intramolecular covalent bonds rather than discrete intermolecular forces.

Paper Chromatography

A technique that separates components of a mixture based on their relative affinities for a stationary phase (e.g., polar filter paper) and a mobile phase (e.g., a developing solvent).

Fractional Distillation

A separation process that separates liquid mixtures based on differences in vapor pressure and boiling points using a fractionating column with an internal temperature gradient.

Esterification Reaction

A dehydration reaction in which a carboxylic acid and an alcohol react to form an ester and water.

Alkane

A saturated hydrocarbon containing only single carbon-carbon bonds, corresponding to the general chemical formula $\text{C}_n\text{H}_{2n+2}$.

Alkene

An unsaturated hydrocarbon containing at least one carbon-carbon double bond ($\text{C}=\text{C}$), corresponding to the general formula $\text{C}_n\text{H}_{2n}$.

Alkyne

An unsaturated hydrocarbon containing at least one carbon-carbon triple bond ($\text{C}\equiv\text{C}$), corresponding to the general formula $\text{C}_n\text{H}_{2n-2}$.

Structural Isomers

Molecules that share the exact same molecular formula but possess different bonding connectivity, resulting in distinct names and physical properties.

Cis-Trans (Geometric) Isomers

Isomers resulting from restricted rotation around a double bond ($\text{C}=\text{C}$), where identical substituent groups are placed on either the same side (cis) or opposite sides (trans).

Lewis Acid

Any chemical species that acts as an electron pair acceptor.

Lewis Base

Any chemical species that acts as an electron pair donor by possessing available unshared lone pair electrons.

Salt Bridge

An electrostatic attraction formed between oppositely charged amino acid side chains (such as $\text{K5.39}^+$ and $\text{D3.32}^-$) to stabilize protein tertiary structure.

Parent Molecular Ion ($M^+$)

The unfragmented ionized molecule in mass spectrometry that typically generates the peak at the highest mass-to-charge ratio ($m/z$), revealing the compound's molar mass.

Fingerprint Region

The complex spectral zone between $600\,\text{cm}^{-1}$ and $1400\,\text{cm}^{-1}$ in infrared (IR) spectroscopy that produces a vibrational pattern unique to each compound.

Unique Hydrogen Environment

A set of proton (hydrogen) atoms in a molecule sharing identical chemical, structural, and magnetic surroundings, resulting in a single unified signal in $^1\text{H-NMR}$ spectroscopy.

Microwave Radiation

Low-energy electromagnetic radiation that induces molecular rotation.

Infrared (IR) Radiation

Intermediate-energy electromagnetic radiation that causes vibrational excitation, forcing covalent bonds to stretch and bend.

Ultraviolet / Visible (UV-Vis) Light

High-energy electromagnetic radiation that causes electronic transitions, exciting valence electrons to higher electronic energy levels.

Alcohol

An organic compound characterized by a hydroxyl group ($-\text{OH}$) bound to a carbon chain, represented by the general formula $\text{R-OH}$.

Ether

An organic compound characterized by an oxygen bridge between two organic groups, represented by the general formula $\text{R-O-R'}$.

Aldehyde

An organic compound containing a carbonyl group located at the terminus of a carbon chain ($-\text{CHO}$), represented by the general formula $\text{R-CHO}$.

Ketone

An organic compound containing an internal carbonyl group ($-\text{C}(=\text{O})-$), represented by the general formula $\text{R-CO-R'}$.

Carboxylic Acid

An organic compound containing a carboxyl group ($-\text{COOH}$), represented by the general formula $\text{R-COOH}$.

Ester

An organic compound characterized by a carboxylate linkage ($-\text{COO}-$), represented by the general formula $\text{R-COO-R'}$.

Amine

An organic nitrogen derivative containing an $-\text{N}-$ or $-\text{NH}_2$ functional group, represented by the general formula $\text{R-NH}_2$.

Amide

An organic compound containing a carbonyl group directly linked to an amine group ($-\text{C}(=\text{O})\text{NH}_2$), represented by the general formula $\text{R-CONH}_2$.