CONCENTRATION

"The measure of the amount of dissolved material (solute) in a solution. It can be expressed in a variety of ways. Expressions in weight percent, and grams of solute per liter of solution are common. A more fundamental way to express concentration is used in chemistry: the ""molar"" concentration. A solution is considered one molar (1 M) if it contains as many grams of solute per liter of solution as is the molecular weight of the solute (the so called gram-mole). This provides an atomistically fundamental expression because one gram-mole of any material will contain the same (and very large) number of molecules. One gram-mole of hydrogen gas contains the exact same number of molecules as one gram-mole of table salt (sodium chloride), even though the latter is much heavier. In this dictionary, the term ""concentration"" always designates ""molarity"" unless otherwise specified. "