Electrochemistry: More Powerful than Thor!

Electrochemsitry

The Norse god of Thunder (and favorite superhero of many) may shoot lightning bolts at his enemies, but if Thor had studied electrochemistry, he could do way more with his powers!

As a master of electrochemistry, Thor would be able to do thinks like corrode the metal bunkers of his enemies into dust… or charge his phone battery in a single *ZAP.* When chemistry gets involved, electricity gets way cooler.

In normal electricity, negatively-charged electrons flow through metallic wires, which have lots of free electrons to “conduct” the charge. In electrochemistry, charged atoms like sodium, chloride, and even hydrogen are often used to carry the charge as well as wires and electrons—and do a lot of cool chemistry on the side.

Reduction Potentials

Electrons are looking for the most comfortable, stable position. If you mix two substances and one has a high-energy, unstable electron it wants to get rid while the other has a lower-energy, stable position just waiting to accept an electron, the electron will flow spontaneously from the unstable position to the stable one. This is called a “redox” reaction, because one species is oxidized—loses an electron—and one is reduced—it gains an electron.

How do you know which is going to be which? Reduction potential tables show you how badly a substance wants to gain an electron, and electrons will flow from species higher up on the table to those lower down on the table, giving off the difference in energy in the process.

That difference in energy is what makes electrochemistry possible. If you put a wire between the two reactants, you can separate the reactions and force the electrons to flow through the wire. That little bit of extra energy can then be used to power a lightbulb, charge your phone, or even make a kosher dill pickle glow (seriously! Just don’t try this without adult supervision. Or touch the glowing pickle).

Once all of the electrons have moved from one side of the reaction to the other, all the energy has been used up. If this is happening in a battery, we say that the battery is dead. In rechargeable batteries, you can plug them into an energy source to force the electrons back over the wire into their original, higher-energy positions, where they’ll sit and wait for the next time you need some power on the go. At that point, the wire is reconnected and energy will flow again.

So when Thor’s cell phone dies, all he has to do is *ZAP* the electrons back through the wire to their starting points, and he’ll have all the power he needs (as long as he doesn’t fry his phone when he tries to recharge the battery).

If Thor wanted to know exactly how much energy he would need to recharge a battery (or how much it produces) without frying it with lightning, he could calculate the cell potential as described in this lecture. Once you have a balanced reaction (yay, stoichiometry!) all you have to do is add up the potentials.

Electrochemistry: Foe of Metal

Electrochemistry can take place between any two species that can gain and lose electrons. Often, these are two metals, like cadmium and lithium or aluminum and iron. Connect them with a wire or a salty, acidic solution that will transfer charge from one side to the other, and you have a battery. That’s why you don’t put aluminum foil on a cast-iron or steel pot of tomato sauce or lasagna—unless you happen to like metal-flavored tomato sauce (seriously, don’t. That stuff’s toxic!).

That reaction looks like this:

2Al + 3Fe2+ + 6e —> Al3+ + 6e + Fe

Do you see how the normal, uncharged aluminum metal becomes aluminum 3+? That means it’s lost three electrons and given them to the iron (probably to iron oxide present on the surface of the iron). This means that the aluminum is not aluminum metal anymore. It’s aluminum ion, which dissolves in water, leaving holes in the aluminum foil and black spots in the tomato sauce. Not good—unless you’re Thor and you need to get through a metal door into an enemy bunker.

In that case, bring on the lasagna (or, you know, more concentrated acid), provide a flow of electrons out of the door and into a receptor, and *BAM!* Holes in doors (although come to think of it, Thor wouldn’t even need a bolt of lightning for that… just some acid and something that can accept the electrons. Maybe he’d be better off just hitting it with his hammer).

Other Powers

Electrochemistry can also be used to cover things in metal (electroplate them—the opposite of putting holes in a sheet of metal); separate hard-to-separate compounds like water into hydrogen and oxygen; and precipitate metals out of a solution (one professor was notorious for

Clearly, Thor’s powers are wasted on thunder and lightning. With a little electrochemistry, his superpowers could be way more awesome.

I mean, what Norse God can resist making a pickle glow like a lightbulb?

Want to learn more? Check out the Cell Potential video in our AP Chemistry course or Electrochemistry lesson in our General Chemistry course.

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