Forming O2 Molecule: Heat or Chemistry?

[dlilpyro]

How do individual oxygen atoms combine to form the O2 molecule? Can it be done with heat?

 

[Drakkith]

Oxygen has several unpaired electrons and is VERY reactive. It will readily form molecules with many different substances, including itself. It doesn't take much to do it.

 

[Nemus]

A situation where this happens is when you electrolyze water. Free oxygen atoms form at the anode and immeadiately recombine to form O2. At room temperature.

 

[Ken Natton]

In chemistry as in other sciences, I must begin by highlighting the fact that I claim no particular expertise. But I have seen a very good explanation of the answer to the exact question you have asked dlilpyro, and it seems to me that I am justified in giving this answer here because no-one else with greater expertise has yet provided it. If the explanation as I give it is imperfect, perhaps it will stimulate a more expert response. If it is wanted, I can provide the details of my source, but I can’t do it now because I am away from home at the moment

The first thing you should know dlilpyro, is that in point of fact, the answer to your question is not actually a chemical one, it is a physical one. It is to do with a phenomenon called ‘ground state’. Within any given circumstances, the electrons in an atom can occupy different energy levels, but the lowest energy level they can occupy in that circumstance and to which they will tend, is called the ground state. But electrons can find lower energy ground states in some circumstances than they can in other circumstances and where possible, they will tend to the circumstance that offers the lowest ground state. So, the reason that atoms of oxygen tend to pair into molecules of O2 is because the electrons in the oxygen atom find a lower ground state as part of an O2 molecule than they do as part of a lone oxygen atom. But that is not the lowest ground state that they can find. The lowest ground state they can find is as part of a molecule of carbon dioxide. That is why atoms of carbon and oxygen tend to form molecules of carbon dioxide when circumstances permit.

 

[Borek]

The lowest ground state they can find is as part of a molecule of carbon dioxide. That is why atoms of carbon and oxygen tend to form molecules of carbon dioxide when circumstances permit.

Up to this moment you were more or less right. There are other compounds, which are even more energetically favorable. Mg burns in carbon dioxide, leaving soot as one of products, so obviously solid MgO is preferred over gaseous CO₂.

 

[dlilpyro]

Thank you for your answers. I am thinking of making a fuel cell for a school project with water as the fuel. Could anyone comment on whether or not this would work and why not? I was thinking of using electrolysis to separate the H2 and the O and then use the subsequent O2 molecules as well as the H2 molecules for power as both are combustible.

 

[dlilpyro]

Anyone?

 

[Nemus]

It will work but you are first taking water apart and then putting it back together...

 

[mishrashubham]

Thank you for your answers. I am thinking of making a fuel cell for a school project with water as the fuel. Could anyone comment on whether or not this would work and why not? I was thinking of using electrolysis to separate the H2 and the O and then use the subsequent O2 molecules as well as the H2 molecules for power as both are combustible.

That is what many people have been trying to do. But apparently you put in more energy into separating H and O than what you get back by combustion.

 

[Drakkith]

Water can be used as a source of fuel, however it is more like a battery than a fuel source since you have to split the water into oxygen and hydrogen, which takes more energy than the combustion of the two provide.