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Stoichiometry III: Calculations Based
on Concentrations of Solutions
When two or more substances are mixed together in a manner that is homogeneous and uniform at the molecular level, the mixture is called a solution. The
component (usually a liquid) that is present in much larger quantity than the
others is called the solvent; the other components are the solutes. The concentration of a solution describes the amount of solute present in a given amount of
solution. When a solution is involved in a reaction, the stoichiometric calculations must take into account two quantities not previously discussed: the concentration of the solution, and its volume.
PREPARATION OF SOLUTIONS
The ways in which chemists most frequently express concentrations involve the
mole as the concentration unit (rather than the gram), because reactions are
between molecules as the basic entities.
Molarity
A solution that contains one mole of solute per liter of solution is known as a
one molar solution; it is abbreviated 1.00 M. In general,