BCHM 3114 Aqueous Chemistry I Flashcards

Vocabulary flashcards covering water structure, molecular dipoles, hydrogen bonding, hydration shells, solubility, and the hydrophobic effect for BCHM 3114 Class 1.

Polar Covalent Bond

A covalent bond in which electron sharing is unequal, causing one atom to carry partial negative character ($\delta^-$) and the other partial positive character ($\delta^+$).

Net Dipole Moment

The overall molecular dipole formed in water because its polar covalent bonds do not cancel due to its bent geometry.

Hydrogen Bond Donor

A molecular group bearing a hydrogen atom covalently attached to an electronegative atom.

Hydrogen Bond Acceptor

An electronegative atom containing an available nonbonding electron pair (lone pair) that can interact with a hydrogen bond donor.

Cohesion

The physical property of water where water molecules remain strongly associated via hydrogen bonds while still moving past one another.

Thermal Buffering

The ability of water to moderate temperature changes because energy is required to disrupt its extensive network of hydrogen bonds.

Hydration Shell

A surrounding structure of water molecules organized around dissolved ions or polar solutes, orienting water's partial charges toward the particle.

Hydrophilic

A term meaning "water-loving," describing molecules or functional groups that interact favorably with water.

Electrolytes

Dissolved ions in solution that allow the liquid to conduct electricity.

Strong Electrolyte

A solute that fully dissolves and dissociates into ions in water.

Weak Electrolyte

A solute that partially dissolves or dissociates into ions in water.

Nonelectrolyte

A solute containing no charged particles when dissolved, showing little to no dissolution into ions.

Hydrophobic Effect

The clustering of nonpolar molecules in water driven by an increase in water entropy as constrained hydration shells coalesce and release ordered water.

Amphipathic Molecules

Molecules that contain both hydrophilic (polar or charged) and hydrophobic (nonpolar) regions.

Micelle

A spherical structure formed by amphipathic molecules in water where hydrophobic nonpolar tails are sequestered in the interior and hydrophilic heads face the aqueous surroundings.

Hexane

A mostly nonpolar hydrocarbon with formula $\text{CH}_3-(\text{CH}_2)_4-\text{CH}_3$ that exhibits weak interaction with water.

2-Hexanol

A six-carbon alcohol with formula $\text{CH}_3-\text{CH(OH)}-(\text{CH}_2)_3-\text{CH}_3$ containing one polar $-\text{OH}$ group and a large nonpolar region, displaying intermediate water interaction.

1,6-Hexanediol

A six-carbon compound with formula $\text{HO}-(\text{CH}_2)_6-\text{OH}$ containing two polar $-\text{OH}$ groups, resulting in stronger water interaction than 2-hexanol.