A solution is a homogeneous mixture —a mixture of two or more substances that are so intimately mixed that the mixture behaves in many ways like a single substance. Many chemical reactions occur when the reactants are dissolved in solution. In this chapter, we will introduce concepts that are applicable to solutions and the chemical reactions that occur in them. 10.1: Prelude to Solutions A solution is a homogeneous mixture—a mixture of two or more substances that are so intimately mixed that the mixture behaves in many ways like a single substance. Many chemical reactions occur when the reactants are dissolved in solution. In this chapter, we will introduce concepts that are applicable to solutions and the chemical reactions that occur in them. 10.2: Definitions Solutions are composed of a solvent (major component) and a solute (minor component). Concentration is the expression of the amount of solute in a given amount of solvent and can be described by several qualitative terms. Solubility is a specific amount of solute that can dissolve in a given amount of solvent. “Like dissolves like” is a useful rule for deciding if a solute will be soluble in a solvent. 10.3: Quantitative Units of Concentration Quantitative units of concentration include molarity, molality, mass percentage, parts per thousand, parts per million, and parts per billion. 10.4: Dilutions and Concentrations Calculate the new concentration or volume for a dilution or concentration of a solution. 10.5: Concentrations as Conversion Factors Know how to apply concentration units as conversion factors. 10.6: Solutions (Exercises)