Ch11-12 IMFs & Solution Properties Vocab

Dipole

Dipole

equal and opposite charges within a molecule (partial positive + negative charges); occurs due to differences in electronegativity

Dipole-Dipole Attraction (dipole interactions)

IMF between 2 polar molecules

Hydrogen Bonding

specific type of dipole-dipole where H and NOF (small, highly electronegative elements) attract each other

London Dispersion Forces

dipole-induced dipole force; temporary dipoles on nonpolar molecules; strength increases w/ number of e-

Ion-Dipole Attraction

attraction between ion and polar molecules

Surface Tension

cohesive force at a liquid’s surface that attracts it to itself

Capillary Action

attraction between liquid and its narrow tube container (meniscus)

Cohesive Forces

attraction between particles of the same type

Adhesive Forces

attraction between particles of one type and particles of another type

Viscosity

a measure of a fluid’s resistance to flow

Crystalline Solids

organized, repeating 3D structure; well-defined melting points

Amorphous Solids

random, no repeating structure; no sharp melting point, gradually melt over a range of temps

Lattice

3D arrangement of points that represent the positions of atoms, ions, or molecules in a crystalline solid

Unit Cell

the smallest repeating unit in a crystal lattice that, when repeated, can recreate the crystal’s entire structure

Alloy

mixture of 2+ elements (1+ is a metal)

Substitutional Alloy

when some of the atoms of the original metal are replaced by atoms of a different metal (same crystal structure as original metal)

Interstitial Alloy

when new, smaller atoms fill the spaces between the larger, original atoms

Vaporization (evaporation)

process of liquid to vapor; evaporation is a specific type of vaporization that occurs when a liquid is below its boiling point

Heat of Vaporization

the amount of energy required to turn one mole of liquid to vapor at constant temp and pressure

Condensation

process of vapor to liquid

Equilibrium

rates of forward and reverse processes are equal; thermodynamic equilibrium is when heat transfer is at its minimum (zero)

Equilibrium Vapor Pressure

pressure exerted by a vapor that is in thermal equilibrium with its condensed phase at a given temp in a closed system; reflects how easily molecules escape from liquid to vapor phase (high IMF = low vapor pressure)

Sublimation

direct transition from solid to gas without passing through liquid phase

Heating Curve

graphical representation of temp change of a substance as it is heated, showing phase changes where temp is constant even as heat is added

Heat of Fusion

amount of heat needed to convert solid to liquid at its melting point without changing temp

Normal Melting Point

temp at which solid becomes liquid under standard atmospheric pressure (1 atm)

Normal Boiling Point

temp at which liquid becomes vapor under standard atmospheric pressure (1 atm)

Superheated

liquid that has been heated above its normal boiling point without it actually boiling (can happen when there are no impurities/nucleation sites to facilitate boiling)

Supercooled

liquid that remains liquid below its normal melting point without crystallizing (can happen when there are no impurities/nucleation sites to facilitate crystallization)

Phase Diagram

graphical representation of a substance’s phases and when they are stable based on temp and pressure

Triple Point

the specific temp and pressure at which all 3 phases coexist in equilibrium

Critical Point

critical temp + critical pressure; marks the end of the phase boundary between liquid and gas; at temps and pressures higher than this point, the substance exists as a supercritical fluid

Critical Temperature

highest temp at which a substance can exist at a liquid (above this temp, no amount of pressure can liquefy the substance)

Critical Pressure

minimum pressure needed to liquefy a substance at its critical temperature