Chemical and Biomolecular Engineering

Official blog of the Lehigh University Chemical Engineers

Electrochemistry

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Electrochemistry is a branch of chemistry that focuses on chemical reactions occurring in solution. These reactions involve the transfer of electrons between molecules, which are also known as redox (reduction-oxidation) reactions. The most well-known example of electrochemistry is the reactions that occur in batteries and fuel cells. Every battery has an anode and cathode, oxidation occurs at the anode and reduction occurs at the cathode. Based on the solution and metal electrodes, one can determine the voltage produced by the reaction. Here is what a simple voltaic cell looks like:

Voltaic Cell

Voltaic Cell

My last two chemistry labs involved electrochemistry. In the first lab, we were given a known concentration of Cu2+ solution and then three unknown metal solutions. We measured the voltage across each combination of metals. Using the Nernst Equation, we can predict the identity of the unknown metals.

In lab this week, we worked with concentration cells. Concentration cells have the same solution in both the anode and cathode, our lab used copper solution. The largest voltage is produced when the difference in concentration is greatest. In order for the system to reach equilibrium, the greatest amount of electrons need to be transferred when the difference between each concentration is greatest. We also looked at the effect of adding ligands to solution. Some ligands formed solids with the copper solution. By finding the voltage produced by each ligand and copper concentration, we could actually determine the solubility constant (Ksp) of each reaction. It was pretty incredible to find an equilibrium constant based on electrochemistry of the system.

Currently, chemists and engineers are investing a great deal in electrochemistry. Scientists are focusing on fuel cells and more efficient batteries. To help preserve the environment and make electric equipment more effective and practical, scientists are constantly studying fuel cells and batteries. Just think about how a small phone battery can power your cell phone all day. The most important current event with electrochemistry is hydrogen-oxygen fuel cells. The redox reaction between hydrogen and oxygen produces a significant amount of current and the only by-product is liquid water. This type of fuel cell is ideal compared to burning hydrocarbons, which produce carbon dioxide. The biggest issue with hydrogen-oxygen fuel cells is obtaining gaseous hydrogen (H2). The most common method is electrolysis of water. Electrolysis causes a redox reaction to run in reverse, in this case hydrogen is produced. The biggest issue is this process is dangerous (H2 is flammable) and takes a great deal of energy. Chemists and engineers are working to find an effective way to produce H2 in order to make hydrogen-oxygen fuel cells practical.

It’s interesting to learn ideas and procedures in lab that are currently being investigated in the real world. I’m excited to eventually take what I’m learning at Lehigh and apply it to real-world applications that impact people’s well-being.

Hydrogen-Oxygen Fuel Cell

Hydrogen-Oxygen Fuel Cell

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Author: Ben Dunmire

I am a sophomore Chemical Engineering major at Lehigh. On campus, I am the president of Club Baseball and a member of AIChE and NSCS. Outside of school, I enjoy the outdoors, fishing, and any type of athletic activity. You can reach me at bcd216@lehigh.edu.

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