LAB 7 (1).pdf - Shantel Boyd Che 105-700D Laboratory 7...

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Shantel Boyd Che 105-700D Laboratory 7 Electrical Conductivity of Aqueous Solutions Objectives The objectives of this laboratory are: a) To observe electrical conductivity of substances in various aqueous solutions b) To determine of the solution is a strong or weak electrolyte c) To interpret a chemical reaction by observing aqueous solution conductivity. Background Electrical conductivity is based on the flow of electrons. Metals are good conductors of electricity because they allow electrons to flow through the entire piece of material. Thus, electrons flow like a “sea of electrons” through metals. In comparison, distilled water is a very poor conductor of electricity since very little electricity flows through water. Highly ionized substances are strong electrolytes. Strong acids and salts are strong electrolytes because they completely ionize (dissociate or separate) in solution. The ions carry the electric charge through the solution thus creating an electric current. The current, if sufficient enough, will light one or both LEDs on a conductivity meter, shown at right. Slightly ionized substances are weak electrolytes. Weak acids and bases would be categorized as weak electrolytes because they do not completely dissociate in solution. Substances that do not conduct an electric current are called non-electrolytes. Non-electrolytes do not ionize; they do not contain moveable ions. The LEDs of a conductivity meter will not light because there are no ions to carry the electric current. The table below lists examples of strong, weak and non- electrolytes. Procedure Safety Be cautious with hydrochloric acid, nitric acid, sulfuric acid and concentrated acetic acid. Although low in concentration, some individuals may have extreme skin sensitivities. If you experience any tingling

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