Chemical World Word List

Acidity

The extent to which a substance displays characteristics common to acids; measured in pH

Activation energy

The minimum energy required by reactants for reactions to occur

Alkalinity

The extent to which a substance displays characteristics common to bases; measured in pH

Aqueous

Dissolved in water

Avogadro’s constant

The number of particles in one mole; NA = 6.022 x 10^23

Catalyst

A substance which lowers the activation energy of and therefore speeds up a chemical reaction. It is neither a reactant nor a product and is not used up in the reaction

Chemical change

A change that results in at least one new substance by a rearrangement of atoms

Collision theory

A theoretical model that accounts for the rates of chemical reactions in terms of collisions occurring during a chemical reaction

Covalent bond

The force of attraction formed when one or more pairs of electrons are shared between two nuclei

Decomposition

A reaction type where a compound is broken down into simpler compounds or its elements

Endothermic

Energy of products is more than energy of reactants; absorbs heat energy

Enthalpy

The total energy possessed by a chemical substance at constant pressure

Exothermic

Energy of reactants is more than energy of products; releases heat energy

Insoluble

Unable to dissolve in a named solvent

Ion

An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

Ionic bond

A type of chemical bonding that involves the electrostatic attraction between oppositely charged ions.

Mole

The amount of substance that contains the number of particles equal to Avogadro’s constant (NA = 6.022 x 10^23)

Molar mass

The mass of one mole of an element or compound

pH

A measure of the acidity or alkalinity of a substance

Physical change

A change of phase (solid

Polyatomic ion

An ion that is made up of more than one element

Product

A substance made by a chemical reaction

Reactant

A starting material for a chemical reaction

Reaction rate

The speed with which reactants are converted to products in a chemical reaction

Salt

An ionic compound

Stoichiometry

The whole number molar ratios of a balanced chemical equation and the resultant calculations of relative amounts of reactants and products.