Chapter 9 – Liquids and Solids

A set of 60 vocabulary flashcards designed to help students review key concepts related to liquids and solids in chemistry.

Intermolecular Forces

Forces of attraction between molecules.

London Dispersion Forces

Weak, temporary attractive forces between molecules caused by fluctuations in electron distribution.

Dipole-Dipole Attraction

Attraction between polar molecules that possess permanent dipoles.

Hydrogen Bonding

Strong type of dipole-dipole interaction that occurs between molecules containing hydrogen bonded to highly electronegative atoms like O, N, or F.

Noncovalent Interactions

Attractive forces that are not covalent bonds, including hydrogen bonds, ionic bonds, and London dispersion forces.

Viscosity

A measure of a liquid's resistance to flow.

Surface Tension

The energy required to increase the surface area of a liquid due to the attractive forces among liquid molecules.

Capillary Action

The ability of a liquid to flow up a narrow tube against the force of gravity.

Phase Change

A transition between different states of matter, such as solid, liquid, and gas.

Enthalpy of Vaporization (ΔHvap)

The heat input needed to convert a liquid into a gas at constant temperature and pressure.

Boiling Point

The temperature at which a liquid's vapor pressure equals the external pressure.

Vapor Pressure

The pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases in a closed system.

Ion-Dipole Attraction

The attraction between an ion and the partial charges in a polar molecule.

Polar Molecules

Molecules that have a net dipole moment due to the presence of polar bonds.

Nonpolar Molecules

Molecules that do not have a net dipole moment; their charge distribution is symmetric.

Critical Point

The end point of a phase equilibrium curve, beyond which distinct liquid and gas phases do not exist.

Triple Point

The specific condition at which all three phases of a substance coexist in thermodynamic equilibrium.

Heat of Fusion (ΔHfusion)

The amount of energy required to change a substance from solid to liquid.

Endothermic Process

A process that absorbs heat from the surroundings.

Exothermic Process

A process that releases heat to the surroundings.

Polarity

A property of molecules that describes the presence of a dipole moment due to differences in electronegativity.

Boiling Point Elevation

The increase in boiling point of a solvent due to the presence of a solute.

Melting Point

The temperature at which a solid becomes a liquid.

Thermal Energy

The total energy of the particles in a substance; related to temperature.

Molar Heat Capacity

The amount of heat required to raise the temperature of one mole of a substance by one degree Celsius.

Phase Diagram

A graphical representation of the physical states of a substance under different conditions of temperature and pressure.

Kinetic Molecular Theory

A theory that describes the behavior of gases in terms of particles in motion.

Raoult's Law

A principle that states that the vapor pressure of a solution is dependent on the vapor pressure of the individual components and their mole fractions.

Heat Capacity

The amount of heat energy required to change the temperature of a given quantity of a substance.

Cohesion

The attractive force between molecules of the same substance.

Adhesion

The attractive force between molecules of different substances.

Molecular Shape

The three-dimensional arrangement of atoms in a molecule.

Electronegativity

The tendency of an atom to attract electrons towards itself.

Dipole Moment

A measure of the polarity of a chemical bond; a vector quantity.

Thermal Equilibrium

The state in which two substances have exchanged thermal energy until they reach the same temperature.

Solubility

The ability of a substance to dissolve in a solvent at a given temperature and pressure.

Sublimation

The phase change that occurs when a solid turns directly into a gas without passing through a liquid phase.

Condensation

The process by which gas transforms into liquid.

Heating Curve

A graphical representation of the phase changes of a substance as it is heated.

Vaporization

The process by which a liquid turns into a gas.

Thermal Conductivity

The ability of a material to conduct heat.

Entropy (ΔS)

A measure of disorder or randomness in a system.

Dynamic Equilibrium

A condition where the rates of forward and reverse processes are equal.

Partial Pressure

The pressure that a gas in a mixture would exert if it occupied the entire volume by itself.

Molar Volume

The volume occupied by one mole of a substance, usually measured in liters.

London Forces

Another term for London Dispersion Forces, which are weak interactions caused by temporary dipoles.

Phase Transition

The transformation of a substance from one state to another.

Liquid Crystal

A substance that exhibits properties between those of liquids and solid crystals.

Critical Temperature

The temperature above which a substance cannot exist as a liquid, regardless of pressure.

Saturation Point

The concentration of a solute in a saturated solution that is in equilibrium with its solid.

Dissociation

The process of breaking down an ionic compound into its constituent ions.

Mole Fraction

The ratio of the number of moles of one component to the total number of moles of all components in a mixture.