states of matter

Intermolecular forces

"Attractive forces between molecules that keep them close to each other."

Attraction forces

"Forces responsible for cohesion between particles of matter."

van der Waals forces

"General term for intermolecular forces including dipole-dipole and London forces."

Dipole-dipole interaction

"Attractive force between polar molecules caused by alignment of opposite partial charges."

Hydrogen bonding

"Weak to moderate attraction between a hydrogen atom bonded to a highly electronegative atom and a lone electron pair on another electronegative atom."

London forces

"Weak intermolecular forces caused by instantaneous dipoles due to electron motion."

Dispersion forces

"Another name for London forces."

Strength of intermolecular forces

"Factor influencing state of matter, boiling point, and melting point."

Dipole moment

"Measure of molecular polarity expressed in debye (D)."

Debye

"Unit of dipole moment where 1 D equals 3.336 × 10⁻³⁰ C·m."

Instantaneous dipole

"Temporary dipole formed by uneven electron distribution."

Polarizability

"Ability of an electron cloud to be distorted."

State of matter

"Physical form of a substance depending on particle motion, distance, and attraction."

Gaseous state

"State where kinetic energy exceeds attraction forces and particles are far apart."

Compressibility of gases

"Ability of gases to decrease volume under pressure."

Ideal gas

"Hypothetical gas that perfectly follows gas laws."

Kinetic theory of gases

"Model describing gas behavior using particle motion."

Assumption of negligible volume

"Ideal gas assumption that particle volume is negligible."

Elastic collision

"Collision where total kinetic energy is conserved."

Average kinetic energy

"Mean energy of gas molecules proportional to absolute temperature."

Absolute temperature

"Temperature measured in kelvin (K)."

Maxwell-Boltzmann distribution

"Distribution describing molecular speeds in a gas."

Most probable speed

"Speed corresponding to the peak of the Maxwell-Boltzmann curve."

Gas laws

"Quantitative relationships between pressure, volume, temperature, and amount of gas."

Boyle's law

"At constant temperature, pressure is inversely proportional to volume."

Charles's law

"At constant pressure, volume is directly proportional to temperature."

Gay-Lussac's law

"At constant volume, pressure is directly proportional to temperature."

Combined gas law

"Relationship combining Boyle's and Charles's laws."

Avogadro's law

"At constant temperature and pressure, volume is proportional to amount of gas."

Ideal gas equation

"Equation pV = nRT describing ideal gas behavior."

Gas constant (R)

"Proportionality constant in the ideal gas equation."

Deviation from ideal gas behavior

"Difference between real gas behavior and ideal gas laws."

Real gas

"Gas that deviates from ideal behavior at high pressure or low temperature."

Van der Waals equation

"Modified gas equation accounting for molecular volume and attraction."

Cohesion constant (a)

"Van der Waals constant accounting for intermolecular attraction."

Volume correction constant (b)

"Van der Waals constant accounting for molecular volume."

Diffusion

"Spontaneous mixing of particles due to random motion."

Graham's law

"Diffusion rate is inversely proportional to the square root of molar mass."

Dalton's law of partial pressures

"Total pressure equals the sum of partial pressures of gases."

Condensed state

"Liquid and solid states of matter."

Liquid state

"State where particles move freely but remain close together."

Solid state

"State where particles vibrate around fixed positions."

Sublimation

"Direct phase transition from solid to gas."

Evaporation

"Transition of liquid to gas at the surface."

Condensation

"Transition from gas to liquid."

Melting

"Transition from solid to liquid."

Freezing

"Transition from liquid to solid."

Boiling point

"Temperature at which vapor pressure equals atmospheric pressure."

Melting point

"Temperature at which solid and liquid phases are in equilibrium."

Heat of fusion

"Energy required for melting or released during freezing."

Heat of vaporization

"Energy required for evaporation or released during condensation."

Phase transition

"Change between states of matter."

Phase diagram

"Graph showing stable phases of a substance as a function of pressure and temperature."

Triple point

"Point where solid, liquid, and gas phases coexist in equilibrium."

Critical point

"Point where liquid and vapor become indistinguishable."

Critical temperature

"Maximum temperature at which a substance can exist as a liquid."

Critical pressure

"Pressure required to liquefy a substance at the critical temperature."

Sublimation point

"Temperature at which solid vapor pressure equals atmospheric pressure."

Freeze drying

"Removal of solvent by sublimation under reduced pressure."

Lyophilisation

"Another name for freeze drying."

Viscosity

"Resistance of a liquid to flow."

Surface tension

"Energy required to increase liquid surface area."

Vapour pressure

"Pressure of vapor in equilibrium with its liquid."

Distillation

"Separation process based on differences in boiling points."

Amorphous solid

"Solid without long-range order in particle arrangement."

Crystalline solid

"Solid with regularly repeating lattice structure."

Anisotropy

"Direction-dependent physical properties."

Unit cell

"Smallest repeating unit of a crystal lattice."

Isomorphism

"Different substances sharing the same crystal structure."

Polymorphism

"Ability of a compound to form different crystal lattices."

Allotropy

"Existence of an element in different structural forms."

Liquid crystal

"State between liquid and solid with directional properties."