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Author Topic: Experiment Electrolysis Of Water With Aluminium Electrode Timelapse Recording  (Read 2279 times)

Offline UltimateTheory

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Physics Experiment Electrolysis Of Water With Aluminium Electrode Timelapse Recording:


Compare results with Gold electrode:
http://www.thenakedscientists.com/forum/index.php?topic=57616.0


 

Offline UltimateTheory

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Electrolysis Of Water With Aluminium And Graphite Electrodes:


Compare differences between these two cases.
There is slightly different volume ratio between gases.
And there is no foam in the left graduated cylinder with negative electrode (that's now Graphite).
 

Offline chiralSPO

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Aluminum is a very reactive metal, and is easily oxidized. The white foam almost certainly contains significant amounts of aluminum oxides or hydroxides. Because it is easier to oxidize aluminum to aluminum oxide than to oxidize water to oxygen, there is significantly less oxygen produced (possibly none--you might check to see if it is actually hydrogen gas that is produced at the aluminum anode; this would be from reaction of the aluminum directly with the water, not from electrolysis)

In the example of the gold anode, it is easier to oxidize water than gold, so the 2:1 ratio holds.

Do you know what the current was during each of the experiments? You can calculate how much of each gas should have been produced by how much charge was passed through the system (I can provide the equations if you like)
« Last Edit: 12/06/2015 15:34:48 by chiralSPO »
 

Offline UltimateTheory

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In Gold experiment to was going from 60 mA to 70 mA or so.
Maybe even up to 80-90 mA. I am not stare ing at it whole 2h, just sporadically.
For my own purposed I am placing watt meter (it's always plugged) on front of camera, and recording.
It's hard enough making timelapse YT video without. Each experiment was repeated maybe 3-5 times. 1 day of working on 1 video.
I don't want to share video where I made some mistake.

In both Aluminium electrodes current was higher than either Gold only and Graphite-Aluminium cases.
If I recall correctly even some times there was 140 mA. I recall seeing also plentiful of 120-130 mA. That's why it ended up in 93 minutes.

In Graphite-Aluminium IIRC there was 110-120 mA. And ended after 117 minutes.

But problem is that current is never constant. It's changing during experiment. While doing Copper electrolysis it can even go from initial 140mA...250 mA to 1100 mA. It's so much that I am always switching it off for a while to drop temperature of water slightly.

The worst est is electrolysis of Iron. It could go above 18 A and shut down whole electricity in the apartment.

Once when there was plentiful of Al2O3/Al(OH)3 flowing on top of container, I turned on electrolysis (after dropping temperature), and it blow up fuse instantly as well (exceeded 18 A).
But there was couple centimeters foam from Aluminium electrodes.
« Last Edit: 12/06/2015 16:11:27 by UltimateTheory »
 

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