GLOSSARY of TERMS

Alloy: A solution of two metals or a metal and a nonmetal that has the properties of a metal. Alloys are created to get the benefits of both metals in one object. Stainless steel is an example of an alloy.

Atom: Smallest particle of an element that has all the properties of that element.

Boiling point: Temperature at which a substance changes from the liquid phase to the gas phase.

Boiling: Process in which the particles inside a liquid as well as those on the surface of a liquid change to the gas phase.

Boyle’s Law: The law explaining the relationship between the volume of a gas and the pressure exerted upon that gas. It states that the volume of a gas is inversely related to the pressure applied. In other words, as the pressure exerted on the gas goes up the volume will go down and vice versa.

Charles’ Law: The law explaining the relationship between the volume of a gas and the temperature of that gas. It states that the volume of a gas is directly proportional to the temperature. In other words, as the temperature goes up the volume goes up and vice versa.

Chemical Changes: Process by a substance becomes a new and different substance.

Chemical Equation: Expression in which symbols, formulas, and numbers are used to represent a chemical reaction.

Chemical Formula: Combination of chemical symbols usually used to represent a compound.

Chemical Property: Property that describes how a substance changes into a new substance.

Chemical Reaction: Process in which the physical and chemical properties of the original substance change as a new substance with different physical and chemical properties is formed.

Chemical Symbol: Shorthand way of representing an element.

Coefficient: Number that is placed in front of a symbol or formula that indicates how many atoms or molecules of the substance are present.

Colloid: Homogeneous mixture in which the particles are mixed together but not dissolved.

Compound: Substance made up of molecules that contain more than one type of atom; two or more elements chemically combined. (ex: NaCl – sodium chloride)

Condensation: Phase change of a gas to a liquid.

Crystal: Solid in which the particles are arranged in a regular, repeating pattern.

Element: Simplest type of pure substance; substance containing only one type of atom. (ex: oxygen, nitrogen, or carbon) Currently there are 109 known elements.

Energy: The ability to do work.

Evaporation: A form of vaporization that occurs only on the surface of the liquid.

Flammability: The ability to burn.

Freezing point: Temperature at which a substance changes from the liquid phase to the solid phase.

Gas Laws: The term used to describe both Charles Law and Boyles Law.

Gas: Phase in which matter has no definite shape or volume.

Heterogeneous mixture: Mixture that does not appear to be the same or of uniform composition throughout.

Homogeneous mixture: Mixture that appears the same or of uniform composition throughout.

Liquid: Matter with no definite shape but with a definite volume.

Melting point: Temperature at which a substance changes from the solid phase to the liquid phase.

Mixture: Matter that consists of two or more substances that are not chemically combined. (ex: salad, salt water) see also: colloids, solutions.

Molecule: structure made up of two or more atoms. The atoms can be the same type or different types of atoms. (ex: O₂ –oxygen gas, NaCl – sodium chloride)

Phase: State in which matter can exist: Solid, Liquid, Gas, or Plasma.

Physical Property: Characteristic that distinguishes one type of matter from another and can be observed without changing the identity of the substance.

Plasma: Phase in which matter is extremely high in energy and cannot be contained by ordinary matter: very rare state of matter on Earth.

Solids: Phase in which matter has a definite shape and definite volume.

Solution: A type of homogeneous mixture in which one substance is dissolved in another. Solutions are sometimes referred to as the "best mixed" mixtures.

Solute: The substance that is dissolved in a solution.

Solvent: The substance that does the dissolving in a solution. (ex: salt water –salt is the solute, water is the solvent. Water is sometimes called the universal solvent because it will dissolve many substances.)

Soluble: Property of matter that means it can be dissolved in water.

Solubility: The amount of solute that can be dissolved in a certain amount of solvent at a specific temperature.

Subscripts: Number placed to the lower right of a chemical symbol to indicate the number of atoms of the element in the molecule.

Sublimation: A form of Vaporization when a solid goes directly to the gas phase without becoming a liquid.

Vaporization: Phase change of a liquid to a gas.