|01-11-2011, 08:38 PM||#1|
Blue Crack Supplier
Join Date: Jan 2005
Location: Gettin' hot in a photobooth....livin it up in Ikeaville
Local Time: 04:11 AM
It's been awhile since I've posted around these parts. I'm sure you've all missed me terribly.
So I'm helping my neighbour's kid out with a chemistry project.
They have to build an electrochemical cell, and the kid has done a good job and is making some permutation of a voltaic pile.
I know the general theory of batteries, redox reactions, electron flow and stuff.
But despite some googling and looking through my textbooks, I can't find a clear explanation of what happens in a voltaic pile cell.
Galvanic cells (where they are in two containers linked by a salt bridge) are easy, one metal simply keeps dissolving into the solution and the other metal takes ions from the solution. But in that case, they are immersed in solutions containing the appropriate ions.
But what happens if we just put, say, copper and zinc together in a salt water or citrus solution???
Any help would be very greatly appreciated.
And the sooner the better! (He has to hand it in at the end of the week)
|01-11-2011, 10:49 PM||#2|
Join Date: Dec 2010
Location: In an event horizon
Local Time: 01:41 PM
Copper(1.9) is more electronegative than zinc(1.65). Hence it attracts more electrons than zinc.
If you place a piece of copper and a piece of zinc in contact with each other, many electrons will move from the zinc to the copper. But it stop as soon as this attractive force is balanced by the force of repulsion between electrons, which happens almost immediately.
But if you put the two metal strips in a conductive solution, and connect them externally with a wire, the charges will flow continually in the circuit, since this arrangement won't allow the saturation of negative charges on the copper plate. In this way, you'll get continuous electrical energy.
The solution just acts as a conductor, so you can use any electrolyte, whether it be an acid, base or salt solution. Lemon, apple or potato juice or other fruits and vegetables juices rich in ions work too.
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