Electrochemistry is a big topic and not always easy to understand. In simple terms, it is the study of chemical reactions during an exchange of electricity between two substances. We were keeping electrochemistry simple when we wrote about the Baghdad Batteries. Let’s dig a little deeper into a topic belonging to the realm of science.
Which Comes First: The Reaction or the Electricity?
Actually either could, depending on the circumstances. When we charge a secondary battery by passing electricity through it, we cause a chemical reaction. Conversely, a chemical reaction creates the electricity we get when we connect the charged battery to a device. Depending on the battery, this device could be as tiny as a single LED, or as large as the national grid in the case of a large solar battery array.
Two Big Thoughts for Keeping Electrochemistry Simple
This dual possibility opens two branches of electrochemical science. On the one hand, we have studies of electrolytic processes when electricity passes through a chemical system. Then, on the other, we have galvanic or voltaic processes where the charged system delivers electrical energy.
A battery is thus an electrochemical cell containing two conductors (or terminals) that receive or deliver the electricity. This energy passes between them through an ionic conductor we call an electrolyte. Let’s wrap this up with an experiment keeping electrochemistry simple as possible.
A Simple Electrochemical Experiment
Place two thin copper bars (electrodes) in a container of distilled water (electrolyte) ensuring the bars do not touch. Connect one of these electrodes to the negative terminal of a nine-volt alkaline battery.
Then use a multi meter – set to the Ω symbol – to connect the other electrode to the positive terminal. You will detect a small movement of the needle as the circuit completes.
Add a small amount of salt to the electrolyte to see electrochemistry in action. The more intense multi meter response is not due to the salt conducting electricity directly though. The sodium and chlorine separate to become positive and negative respectively, thereby increasing the connectivity of the distilled water itself.
Preview Image: Galvanic Cell