Chemical Equations

Balanced Chemical Equation

A chemical equation in which mass is conserved and each side of the equation has the same number of atoms of each element.

Oxidation-Reduction Reaction

A chemical reaction that involves the transfer of electrons between atoms or molecules, changing the oxidation state of the reactants; the atom or molecule that gains electrons is oxidized, and the atom or molecule that loses electrons is reduced.

Double-Replacement Reaction

A chemical reaction where two compounds exchange chemical bonds to form two products with bonding properties similar to those of the reactants; the general equation is: AX + BY → AY + BX.

Activity Series

A list of metals ranked by their ability or tendency to react with other substances.

Coefficient

A number placed in front of a chemical symbol or formula during the balancing of the equation.

Precipitation Reaction

A reaction that results in the precipitation of a solid from a solution. The general equation is: AX (aq) + BY (aq) → AY (aq) + BX (s).

Combination Reaction

Also known as a synthesis reaction; two or more reactants will combine during a chemical change to create one product. The general equation is: A + X → AX.

Single-Replacement Reaction

In this type of reaction there are two reactants: one single element and one compound. During the reaction, one element replaces another during the chemical change. The general equation is A + BX → AX + B.

Law of Conservation of Mass

Mass is conserved and is neither created nor destroyed in a non-nuclear change. The total mass of the reactants equals the total mass of the products.

Product

The ending substance(s) written on the right side of the chemical reaction arrow, that are created during a chemical change.

Mole Ratio

The ratio between the numbers of moles of any two substances involved in a chemical reaction.

Reactant

The starting substance(s) written on the left side of the chemical reaction arrow, which will be destroyed during a chemical change.

Acid-Base Reaction

This type of double-replacement reaction occurs when equal amounts of an acid are added to a base so that the acid and the base neutralize each other, forming water and salt. The general equation is: HX (acid) + MOH (base) → H2O (l) + MX (salt).

Combustion Reaction

This type of reaction is an oxidation process in which a compound containing carbon, hydrogen, and sometimes oxygen reacts with oxygen gas to produce carbon dioxide gas and water. The general equations are: CxHyOz + O2 → CO2 + H2O or CxHy + O2 → CO2 + H2O

Decomposition Reaction

Where a single compound on the reactant side breaks down into two or more products during a chemical change. The general equation is AX → A + X.