Molarity

Another way of expressing concentration, the way that we will use most in this course, is called molarity. Molarity is the number of moles of solute dissolved in one liter of solution. The units, therefore are moles per liter, specifically it's moles of solute per liter of solution.

molarity = moles of solute liter of solution

The molality of a solution is calculated by taking the moles of solute and dividing by the kilograms of solvent.

Normality

When you need to compare solutions on the basis of concentration of specific ions or the amount of charge that the ions have, a different measure of concentration can be very useful. It is called normality.

Stoichiometry (sometimes called reaction stoichiometry to distinguish it from composition stoichiometry) is the calculation of quantitative (measurable) relationships of the reactants and products in chemical reactions (chemicals).