Guia para preparo de solulções

Laboratory Solution Preparation
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. The Flinn Laboratory Solution Preparation reference section is designed for both the novice and experienced solution maker. It provides valuable information on the basic concepts of preparing solutions and instructions for preparing most solutions required in the high school science laboratory. Professional quality solutions are possible when high quality and fresh chemicals and solvents are used, and meticulous procedures

• Basic concepts of preparing solutions • Over 300 recipes of common laboratory solutions • Solution preparation tips

are followed. Many of the solutions described in this section are available ready-made from Flinn Scientific to save valuable laboratory prep time. The section is divided into several parts for your convenience.
 Basic concepts of preparing solutions  Preparation of simple inorganic salt solutions  Preparations of acid and base solutions  Recipes for Biological, Histological, and Chemical solutions

Basic Concepts of Preparing Solutions
Molarity
• Determine molarity (M1) of starting, more concentrated solution. • Calculate volume of starting solution (V1) required using equation 2. Note: V1 must be in the same units as V2. eq. 2. M1V1 = M2V2 • Example: Prepare 100 mL of 1.0 M hydrochloric acid from concentrated (12.1 M) hydrochloric acid. M1V1 = M2V2 (12.1 M)(V1) = (1.0 M)(100 mL) V1 = 8.26 mL conc. HCl Add 8.26 mL of concentrated HCl to about 50 mL of distilled water, stir, then add water up to 100 mL.

The most common unit of solution concentration is molarity (M). The molarity of a solution is defined as the number of moles of solute per one liter of solution. Note that the unit of volume for