Chapter 6: Intermolecular Forces: Attractions between Particles

intermolecular force

Attraction between two molecules and/or particles (i.e., atoms and ions).

temporary dipole

The separation of charge produced in an atom or molecule by a momentary uneven distribution of electrons; also called induced dipole.

London dispersion force

An intermolecular force between atoms or molecules caused by the presence of temporary dipoles in the atoms or molecules

polarizability

The relative ease with which the electron cloud in a molecule, ion, or atom can be distorted, inducing a temporary dipole.

hydrocarbon

A compound whose molecules contain only carbon and hydrogen atoms.

alkane

A hydrocarbon in which each carbon atom is bonded to four other carbon or hydrogen atoms.

constitutional isomer

One of a set of compounds with the same molecular formula but different connections between the atoms in their molecules; also called structural isomer.

viscosity

A measure of a fluid's resistance to flow.

dipole–dipole interaction

An attraction between regions of polar molecules that have partial charges of opposite sign.

organic compound

A molecule containing carbon atoms whose structure typically consists of carbon–carbon bonds and carbon–hydrogen bonds and that may include one or more heteroatoms such as oxygen, nitrogen, sulfur, phosphorus, or the halogens

functional group

A group of atoms in an organic compound's molecular structure that imparts characteristic physical and chemical properties.

carbonyl group

A functional group that consists of a carbon atom with a double bond to an oxygen atom.

ketone

An organic compound in which the carbon atom of a carbonyl group is bonded to two other carbon atoms.

hydrogen-bonding interaction

A strong dipole–dipole interaction, which occurs between a hydrogen atom bonded to a N, O, or F atom and another N, O, or F atom.

hydroxyl group

A functional group that consists of an oxygen atom with a single bond to a hydrogen atom.

alcohol

An organic compound whose molecular structure includes a hydroxyl group bonded to a carbon atom that is not bonded to any other functional group(s).

ether

An organic compound that contains an oxygen atom with single bonds to two carbon atoms

ion–dipole interaction

An attractive force between an ion and a molecule that has a permanent dipole.

sphere of hydration

The cluster of water molecules surrounding an ion in an aqueous solution.

solvent

The component of a solution for which the largest number of moles is present.

solute

Any component in a solution other than the solvent. A solution may contain one or more solutes.

solubility

The maximum quantity of a substance that can dissolve in a given volume of solution.

miscible

Capable of being mixed in any proportion (without reacting chemically).

dipole–induced dipole interaction

An attraction between a polar molecule and the oppositely charged pole it temporarily induces in another molecule.

hydrophobic

Describes a "water-fearing" interaction between a solute and water that decreases water solubility based on the lack of attraction between solute particles and water molecules.

hydrophilic

Describes a "water-loving" interaction between a solute and water that increases water solubility based on the mutual attraction between solute particles and water molecules.

pressure (P)

The ratio of a force to the surface area over which the force is applied.

standard atmosphere (atm)

The average pressure at sea level on Earth.

phase diagram

A graphical representation of the dependence of the stabilities of the physical states of a substance on temperature and pressure.

triple point

The temperature and pressure at which all three phases of a substance coexist. Freezing and melting, boiling and condensation, and sublimation and deposition all proceed at the same rate, so no net change takes place in the system.

critical point

A specific temperature and pressure at which the liquid and gas phases of a substance have the same density and are indistinguishable from each other.

supercritical fluid

A substance in a state that is above the temperature and pressure at the critical point, at which the liquid and vapor phases are indistinguishable.

green chemistry

Laboratory practices that reduce or eliminate the use or generation of hazardous substances.

surface tension

The ability of the surface of a liquid to resist an external force.

meniscus

The concave or convex surface of a liquid.

capillary action

The rise of a liquid in a narrow tube as a result of adhesive forces between the liquid and the tube and cohesive forces within the liquid.