Lab 11 Electrolytes and Conductivity Purpose To determine if a solution is an electrolyte. Date: Chemical Background Aqueous (aq) – solution with water as the solvent. Electrolyte – solution that conducts electric current. When an ionic solid dissolves in water, the solid dissociates (splits) into cations & anions. NaCl (s)  Na + (aq) + Cl - (aq)

Experiment 1. Set up a conductivity circuit as shown. 2. Test each of the following solutions. 3. Dissolve a small scoop of each solid in distilled water. 4. Wipe dish and test leads clean for each new solution. 5. Discard all solutions in the drain except the last 2.

Solution Formula Conductivity (Strong, Week, Non) Pure Water Tap Water Sodium Chloride (aq)NaCl Potassium Chloride (aq)KCl Sugar (aq)C 12 H 22 O 11 Baking Soda (aq)NaHCO 3 Epsom Salt (aq)MgSO 4 Ethanol (aq)C 2 H 5 OH Vinegar (aq)CH 3 COOH

Analysis 1.Which substances are most likely to possess ionic bonds? 2.If a certain amount of NaCl was dissolved in water, how would the number of Na + ions compare to the number of Cl - ions? Results: This space is for YOUR statement that should summarize what an electrolyte is AND which of the solutions you used were electrolytes.

Questions 1.Does this experiment give qualitative or quantitative conductivity results? 2.Explain why some of the solids conduct current when they are dissolved in water. 3.Why was it important to dissolve the solids in distilled water rather than tap water? 4.Pure water is not an electrical conductor. So why should we be careful with electricity around water? 5.Gatorade (and other sports drinks) advertise that they have electrolytes that will replace those lost during exercise. In terms of the nervous system, why is it important to replace the electrolytes?