Term | Definition |
anhydrous | Pertaining to a hydrate that has lost water from its crystalline structure. |
balanced chemical equation | A chemical equation in which coefficients are arranged to show the conservation of mass in a reaction. |
binary acid | A molecule that consists of hydrogen and one other nonmetal that are dissolved in water. |
binary covalent compound | A compound consisting of two different nonmetal atoms. |
catalyst | A substance that changes a reaction rate without being permanently changed in the process. |
chemical equation | An expression that represents the reactants and products in a chemical reaction by using chemical formulas, symbols, and numerical coefficients. |
decomposition reaction | A chemical reaction of the general from AB → A + B in which a reactant breaks down into two or more simpler products. |
double replacement reaction | A chemical reaction of the general form AY + BZ → AZ + BY, in which the cation of one compound combines with the anion of another compound, and vice versa. |
Greek prefix system | Nomenclature that indicates how many atoms of each element are in a binary covalent compound or how many water molecules are in a hydrate. |
hydrate | A compound that holds a characteristic number of water molecules within its crystalline structure. |
ionic equation | An equation that represents all the substances present during a reaction, including the spectator ions, nonionic products, and insoluble precipitates; written only for reactions taking place in a solution. |
net ionic equation | An equation that shows only the substances involved in a reaction and excludes spectator ions. |
nomenclature | A system of naming that follows a standardized set of rules. The International Union of Pure and Applied Chemistry developed a nomenclature for compounds. |
oxidation number | The number of electrons (the charge) that an atom in a compound must gain or lose to return to its neutral state; also called an oxidation state. |
oxyanion | An anion that contains oxygen and one other element, such as SO 4 2-. |
polyatomic ionic compound | An ionic compound that contains polyatomic ions. |
precipitate | A solid that settles out of a solution as the result of physical or chemical changes. |
product | An element or compound that is the result of a chemical reaction and is written to the right of the arrow in a chemical equation. |
reactant | An element or compound that undergoes a chemical change and is written to the left of the arrow in a chemical equation. |
reactivity series | A table of metals (plus hydrogen) arranged in order of descending chemical reactivity; also called activity series. |
reversible reaction | A reaction that proceeds in a forward and reverse direction so that products can change back into reactants and an equilibrium can be reached. |
single replacement reaction | A chemical reaction of the general form A + BZ → B + AZ, in which a reactive element replaces a less reactive element in a compound; also called a displacement or substitution reaction. |
spectator ion | An ion present on both sides of an ionic equation. It does not participate in the reaction. |
Stock system | A convention used to show the different oxidation states of the same metal ion in an ionic compound. |
synthesis reaction | A chemical reaction of the general form A + B → AB in which two or more reactants combine into a single product. |
ternary acid | A molecule that contains three different elements - hydrogen, oxygen, and another nonmetal. The oxygen and other nonmetal are often combined in a polyatomic ion. |