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INTRODUCTION
Many of the reagents used in science are in the form of solutions, which need to be purchased or prepared. For many purposes, the exact value of concentration is not critical; in other cases, the concentration of the solution and its method of preparation must be as accurate as possible.
Professional quality solutions are possible when high quality and fresh chemicals and solvents are used, and meticulous procedures are followed.
BASIC TERMS AND CONCEPTS OF PREPARING SOLUTIONS.
Normality: A concentration unit (N); defined as the number of equivalents of solute per liter of solution (e.g., 1 M H2SO4= 2 N H2SO4)
Saturated Solution: A solution that contains the maximum amount of a particular solute that will dissolve at that temperature.
Solute: The substance, which is dissolved, or has gone into solution (typically a solid).
Solution: A uniform homogeneous mixture of two or more substances. The individual substances may be present in varying amounts.
Solvent: The substance which does the dissolving (typically a liquid, such as water or alcohol). Must be greater than 50% of the solution.
Standard Solution: A very precise solution, usually to 3–4 significant figures, used in quantitative analysis or an analytical procedure.
Supersaturated Solution: A solution that contains more solute than equilibrium conditions allow; it is unstable and the solute may precipitate upon slight agitation or addition of a single crystal.