Seperating water.

totokan · Post by **totokan** » Thu Apr 19, 2007 6:31 pm

I've got a chem project, and I need some help. Electrolysis is easy enough, electric current flowing into graphite rods in salt water. What I need help with is some way to keep the two gases separate. When they collect on the two rods, they are just bubbles, and I need to store them somehow. I'm able to collect them with a test tube myself, but I wish for a way that doesn't require my holding of the test tube so as to allow myself to finish the rest of the experiment.
EDIT: Oh, yeah. I'm back in case anyone noticed I left. Doubtful, though.

Felino · Post by **Felino** » Thu Apr 19, 2007 6:36 pm

Ok, withou using special equiptment, you can still do this. Here s a dead outsimple way to do it.

Have a large beaker of water (or other container) set upright two filled test tubes, so that their bottoms (opening) is under water, and there is no air bubbles in the tubes. Insert you anode and cathode (that should be spelt with a k).

And hey presto! Seperate gases! (I post a picture soonish)

-Felino

EDIT: Sprta like this, its a side on view. The red wires (yes wires!) are the anode and cathode.

Post by **Triton** » Thu Apr 19, 2007 6:39 pm

i can come up with some ways but they all involve some work, easiest in my opinion would be a sealable container with an airtight lid with two holes oppisite sides above each rod, have a devider between the two sides from the bottom of the lid to just below the water to seperate the gasses further, run hoses to seperate airtight containers or something like that?

totokan · Post by **totokan** » Thu Apr 19, 2007 6:45 pm

Thanks Triton that should work, but I'd need to find tubing? Felino's method is similar to what I am already doing, and has the added benefit of allowing me to just take one tube out and do a "match test".

Post by **Triton** » Thu Apr 19, 2007 6:47 pm

something like fishtank air hose tubing would work, or bigger or smaller, whatver you have should work, felinos is a lot simpler tho lol

Felino · Post by **Felino** » Thu Apr 19, 2007 7:06 pm

Thanks, it works too, and is simple, and easy to set up, for that last time I used a 5-12v (not sure what) 5amp power supply for it. What do you want this for?

With tritons idea, there is one major flaw (no offence) what will the sealable containers at the end have in them, a vaccum? If there was air in there, the tubes would just leak, and no gass would go into the containers, and if it did, it would mix with the air, and defeat the idea of this.

-Felino

bgnome · Post by **bgnome** » Thu Apr 19, 2007 7:13 pm

the classic example is to use upturned glass, such as a beaker or test tube, full of water to catch the oxygen or hydrogen. that way you dont have to worry about air-tight seals or vacuums.

Post by **Triton** » Thu Apr 19, 2007 7:42 pm

yea it wasnt a perfect plan, just what came off the top of my head first lol, your idea wins because of KISS (keep it simple, stupid!) lol

Felino · Post by **Felino** » Thu Apr 19, 2007 7:45 pm

Thanks.

Am.. I... stupid?

totokan · Post by **totokan** » Thu Apr 19, 2007 7:53 pm

Thanks, that looks good. I'm using a psu from a compy modified to a shop power, whoever asked about my power usage. I have lots of old PSU's, and I use them for this purpose. This is an experiment for a class I'm taking now. Felino, the anode and cathode placement, does it matter which one is where? Just which gas is in which beaker changes if they are switched, correct?

Felino · Post by **Felino** » Thu Apr 19, 2007 8:27 pm

Nope, it shouldn't, but there will be twice as much Oxygen as Hydrogen, because water is H2O.

But you should know that!

limpport · Post by **limpport** » Thu Apr 19, 2007 10:26 pm

Just in case you don't know (for some reason), there will be a deadly gas released if you're doing anything with salt water.

Here's a Wikipedia Page about electrolysis of water. The picture is basically the same as Felino's.

Felino wrote:Nope, it shouldn't, but there will be twice as much Oxygen as Hydrogen, because water is H2O.

But you should know that!

Um... Wouldn't there be twice as much hydrogen as there is oxygen? Because water is 2 parts hydrogen, and 1 part oxygen.

TheOnlyOneHeFears · Post by **TheOnlyOneHeFears** » Fri Apr 20, 2007 12:02 am

Yeah, limpport's right, it's 2 parts hydrogen to 1 part oxygen. The 2 in H2O refers to the H, not the O

Felino · Post by **Felino** » Fri Apr 20, 2007 1:16 am

Meh, I knew that, just um, testing you. I was tired when I wrote that.

totokan · Post by **totokan** » Fri Apr 20, 2007 4:20 am

Yeah, I know about the salt releasing chlorine. I've replaced it with pure sodium as a electrolyte/solute