Embedded Files
LAB RELATED MATERIALS
Natural Indicator Lab
An Introduction to Natural Indicators
Weak and Strong Acids & Bases Lab
Measuring Conductivity
Conductivity (the ability of a substance to conduct electricity) can be tested several ways. An electric current can be created two ways: first by the movement of electrons through an object (like a wire) or secondly by the movement of charged atoms or ions. If a substance dissolves in water it may release ions into the water. These ions can conduct a current depending how many ions are present. The more ions released, the stronger electric current that can be created.
Solutions that can conduct an electric because they contain ions are called electrolytes. The more ions that are present in an electrolyte solution, the larger the electric current that can be conducted. You learned in class that acids and bases both release ions when they are added to water. Acids release hydrogen ions (H+) and bases release hydroxide ions (OH-) in water.
In a laboratory, conductivity is best measured with a conductivity meter. Most meters can read a specific range of conductivity. Most hand held meters read from 0 to about 20000 μS (microsiemens – unit of electrical charge). Distilled water, because of its lack of ions, often will produce readings on a conductivity meter of between 0 to 25 μS depending on the source of the water. Tap water will typically produce a reading from 200 to 500 μS due to Cl- ions added by city water treatment plants to kill bacteria and make drinking water safe to consume. Typically, substances that produce readings above 100 μS are considered to be conductive.
Conductivity meters are extremely sensitive to the presence of ions in water. Is it very important to rinse the sensor with distilled water between reading samples to remove any leftover ions so readings are accurate. To test conductivity of a specific substance, you should obtain approximately 1 gram and add it to about 50 mL of distilled water in a beaker. Make sure the opening on the bottom of the probe is submerged in the liquid.
Titration Lab
Using a Buret - Clarke College - Chemistry Department - Dubuque, IA
Titrations - by Carolina Biological Supply
Equipment and Techniques for Titrations by Flinn Scientific
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