Solids, Liquids, and Gases Terms

The attractive forces between unlike molecules.

Amorphous Solids

A solid that does not have a repeating, regular three-dimensional arrangement of particles.

Aqueous

A substance dissolved in water.

Equal volumes of an ideal gas contain equal numbers of molecules if both volumes are at the same temperature and pressure.

Boiling Point (or Vaporization)

The temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure.

Boiling Point Elevation

The boiling point of a solution is higher than the boiling point of the pure solvent (colligative property).

Boyle's Law

The pressure of an ideal gas is inversely proportional to its volume if the temperature and amount of gas is held constant.

Capillary Action

The movement of a liquid along the surface of a solid caused by the attraction of molecules of the liquid to the molecules of the solid.

Charles' Law

The volume of a gas is directly proportional to its temperature if pressure and amount of gas remain constant.

Chemical Process

A method of changing one or more chemicals or chemical compounds.

Cohesive Forces

The intermolecular forces which cause a tendency in liquids to resist separation.

Colligative Properties

Properties of a solution that depend on the number of solute molecules present but not on the identity of the solute.

Combined Gas Law

The gas law that combines Boyle's Law, Charles' Law, and Gay-Lussac's Law.

Compound

Combinations of two or more elements.

Compressibility

A measure of the volume change of a fluid or solid as a response to a pressure.

Condensation

The conversion of a gas into a liquid.

Condensed Phase

Either the solid or liquid phase of a substance.

Covalent Bond

A very strong attraction between two or more atoms that are sharing their electrons.

Covalent Crystal

A crystal in which the structure is maintained by covalent bonds.

Crystal Lattice

A three-dimensional array of points that embodies the pattern of repetition in a crystalline solid.

Crystalline Solid

A solid that possesses long-range order at the atomic or molecular level in its structure.

Dalton's Law Of Partial Pressures

The total pressure exerted by a mixture of gases is the sum of the partial pressure of the individual gases.

Density

Mass of a substance per unit volume.

Deposition

The transition from a gas to a solid.

Dissociation

When ionic substances dissolve their ions while surrounded by solvent molecules and separated from each other.

Effusion

Gas molecules in a container escape from tiny pinholes into a vacuum with the same average velocity they have inside the container.

Electrostatic Force

A phenomenon resulting from slow-moving electrical charges.

Element

A pure substance that cannot be decomposed.

Evaporation

Vaporization of a liquid below its boiling point.

Filtration

The act of passing a liquid or gas through a filter to remove solid particles.

Fluid

Substances (gases and liquids) that flow freely.

Freezing

The conversion of a liquid into a gas.

Freezing Point

The temperature at which the vapor pressure of a liquid is equal to the vapor pressure of the corresponding solid.

Freezing Point Depression

The freezing point of a solution is lower than the freezing point of the pure solvent (colligative property).

Gas

Matter in a form that has low density, is easily compressible, expands spontaneously when placed in a larger container, and has particles that are far apart and move freely

Graham's Law

The rates of effusion of gases are inversely proportional to the square roots of their molecular weights or densities.

Heat

A means by which energy is transferred from a hot body to a colder body when the two are placed in thermal contact with one another.

Heterogeneous

A sample of matter consisting of more than one phase.

Homogeneous

A sample of matter consisting of a single phase,

Hydrogen Bond

Strong dipole-dipole forces between molecules X-H … Y, where X and Y are small electronegative atoms and H denotes the hydrogen bond.

Hydrostatic Pressure

The pressure exerted by a liquid when it is at rest.

Ideal Gas

A gas whose pressure P, volume V, and temperature T are related by PV = nRT, where n is the number of moles of gas and R is the ideal gas law constant.

Ideal Gas Law

The product of pressure and the volume of an ideal gas is directly proportional to the number of moles of the gas and the temperature.

Intermolecular Force

An attraction or repulsion between molecules.

Ionic Crystal

A crystal held together by Coulomb attractions.

Kinetic Energy

The energy an object possesses as a result of its motion.

Kinetic Molecular Theory

A collection of postulates that describe the behavior of molecules in a gas.

Liquid

A state of matter that has a high density, low compressibility, takes the shape of their container, and possesses particles that are close together but are still able to flow.

Mass

The quantity of matter in a body.

Matter

Anything that has mass and volume.

Melting

The process of a solid becoming a liquid.

Melting Point

The temperature at which liquid and solid coexist in equilibrium.

Metallic Crystal

A crystal in which the atoms are linked by electrons shared in delocalized valence orbitals.

Mixture

A sample of matter composed of two or more substances each of which retains its own identity and properties.

Molality

Concentration of a solution measured as moles of solute per kilogram of solvent.

Molarity

Concentration measured as the number of moles of solute per liter of solution.

Mole Fraction

Concentration of a substance in a mixture measured as moles of the substance per mole of mixture.

Molecular Crystal

A crystal in which groups of strongly linked atoms or molecules are held in position by weak intermolecular interactions.

Osmotic Pressure

The pressure that develops in a solution separated from a solvent by a membrane permeable only to the solvent.

Partial Pressure

The independent pressure exerted by different gases in a mixture.

Particle

The building block of matter usually in the form of atoms, molecules, or ions.

Phase

A sample of matter that is uniform throughout both in its chemical composition and in its physical state.

Phase Diagram

A map that shows which phases of a substance are most stable for a given set of pressure and volume conditions.

Physical Change

A change which does not transform one substance into another.

Pressure

Force per unit area.

Raoult's Law

Applies to a gas-liquid mixture when a gas is highly soluble in a liquid and relates the mole fractions of the species in the liquid and gas phases.

Saturated Solution

A solution in equilibrium with a solid state.

Solid

A dense rigid state of matter with a definite volume and shape whose particles are packed close together.

Solubility

The solubility of a substance is its concentration in a saturated solution.

Soluble

Capable of being dissolved in a solvent.

Solute

A substance dissolved in a solvent to make a solution.

Solution

A sample of matter consisting of more than one pure substance with properties that do not vary within the sample.

Solvent

The medium of a solution.

Standard Pressure

Standard pressure has a pressure of 1 atmosphere (atm).

Standard Temperature

Standard temperature is a temperature of 0ºC.

Standard Temperature And Pressure (STP)

Conditions in which pressure is 1 atm and temperature is 0ºC

Sublimation

The process of a solid becoming a gas.

Substance

A sample of matter that has the same chemical composition and physical properties.

Surface Tension

The force per unit length used to overcome the microscopic forces between molecules at the liquid-air interface.

Suspension

A heterogeneous mixture in which solute particles settle out of a solvent after some time has passed.

Temperature

A property associated with the hotness or coldness of an object.

Triple Point

The state at which all three phases coexist in equilibrium.

Unit Cell

The simplest arrangement of atoms or molecules that regularly repeat in a crystal structure.

Universal Gas Constant

The constant in the Ideal Gas Law, equal to 8.3145 J mol-1 K-1 or 0.082058 L atm mol-1 K-1.

Van Der Waals Force

A force acting between non-bonded atoms or molecules.

Vapor Pressure

The pressure of the vapor coexisting with a confined liquid or solid at any specified temperature.

Vaporization (or Boiling Point)

The temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure.