i know this is basic stuff, but how do you take hydrogen out of water?

[cameron marical]

ive ben wondering how they can take hydrogen out of water. i know this is highschool science, but, im in high school so its ok. please, and thanks.

[DrDNA]

You just need a 9V battery and some wires, although carbon electrodes work better if I recall correctly.

When you balance the half reactions as acid:

At the negatively charged cathode, a reduction reaction occurs, so electrons are given to protons to form hydrogen gas

At the positively charged anode, an oxidation reaction occurs, generating oxygen gas.

 

Overall reaction: 2H2O(l) → 2H2(gas) + O2(gas)

 

Of course you realize that hydrogen gas is explosive, especially so in the presence of purified oxygen, right?

[cameron marical]

ya, i do. i was just wondering because ive read about how on the iss{international space station} they purify used water and then turn that into the oxygen they breath. why dont they just keep that water as water and just recycle that by itself using these nano tubes their using for water recyclment here? and then have something that recycles the carbon monoxide we breath out to oxygen{like algae}? arent gases way easiser to store than liquids? you can compress gases and their not as heavy.

[DrDNA]

........just recycle that by itself using these nano tubes their using for water recyclment here?........

Re: Nano

Except for particular experiments that the astronauts might perform as part of their missions, the technology that goes up on the shuttle/space station is usually not cutting edge.

Most of it is decades old.

It is too risky to rely on anything that has not been shown to be reliable.

 

.and then have something that recycles the carbon monoxide we breath out to oxygen{like algae}?

Each astronaut outputs about 1 kg/day CO2

And they do things like this to remove it and turn it into something useful:

CO2 (G) + 2LiOH (S) --> LiCO3 (S) + H2O (L).

There may be other ways as well.

I'm fairly certain that they are looking at things along the lines of algae for settlements on Mars and other long missions.

 

.......arent gases way easiser to store than liquids? you can compress gases and their not as heavy.

Not really.

And molecule for molecule a particular gas is exactly the same weight as the liquid.

Plus, when you compress a gas......it becomes.....a liquid.

[cameron marical]

CO2 (G) + 2LiOH (S) --> LiCO3 (S) + H2O (L).

hmm. how do they do this?

[tyrannt]

It is important to remember, and many people look this over, electrolysis for splitting water into hydrogen and oxygen takes a lot of energy. That is why we don't have a lot of hydrogen cars yet. It would be more efficient to just have electric cars. This can be proven by taking a battery and observing what volume of gas it produces in relation to the total energy the battery exerts. Then, compare this value to the power production capability to the space station and how much oxygen is consumed by the people onboard.