Chemistry

[Ganymede12]

I caught the end of How the Universe Works and it explained that, under very high pressures, Hydrogen becomes metallic, this is what happens at Jupiter's core.

If this is the case, then...

• Is there a way to reverse this process?
  
• Can you make a metal Non-Metallic?
  
• What happens to metals at extreme pressures?
  
• Could we use metal Hydrogen as a material?
  

[sologuitarist61]

Just watched the same programme (recorded)

I guess the answer to points 1 & 2 is to just release the pressure - make sure you stand well back though I'll leave points 3 & 4 to others with more knowledge than me.

[SionR25]

For questions 1+2 the answer is just to release the pressure or heat it up.... a lot.

For question 3 it depends on the metal, some go transparent and some have other changes. A bit more complicated some experience changes in their electron orbitals, E.G. p + s subshells change for transition metals which causes a rearrangement of the electron structure.

I don't think it would be viable to use metal hydrogen as a material, unless it was found to have superconducting properties, in which case it might be worthwhile.

Sion

[username]

Yep for 1 and 2 the first thing that should pop in to your head is : pV = nRT

3; there's too many variables as the states of the metal and properties would aslo be dependent on their temperature. However you could probably relate it too the period and row of the periodic table. It exists in that form for a reason.

4; I think there's a lot of research in to metallic hydrogen at the moment but the biggest problem I see for it actually being of use is the conditions needed to keep it in a metallic state. If i was designing something that required a superconductor I would already be factoring in cold temperatures so insulation would be of great importance but to factor in extremely high pressures as well it may become extremely expensive when other materials exist

[Ganymede12]

I'd like to point out, at this point, that I'm just finishing Yr9 in school so my knowledge of physics and chemistry isn't superb (give it a few years though...).

This in mind try and make it it bit more simple!

I understand most of what has been said but I've never seen pV = nRT before.

[sologuitarist61]

Don't worry about Ganymede, I've never heard of it either

[JulianO]

Its the ideal gas law.

pressure x volume = no. moles * gas constant * temperature.

so if you keep the amount the same (n) and the constant is constant, it means pressure, volume and temperature are all related.

Increase temperature, and either the pressure or volume will go up (or both).

Similarly increasing pressure leads to increase in temperature.

but in this case, if pressure drops, and the temperature can't go much cooler, the only way to balance this is to increase the volume!

[username]

Ganymede, I'm really sorry. I thought I was replying to a thread by someone else who i've seen in this section was studying science at a bit of a higher level and I have an annoying habit when students ask questions of just pointing them in the right direction....

Paying attention has never been one of my strong points

JulianO summed it up nicely though.

[Capricorn]

Isn't it just that at extreme pressures and temperatures then Hydrogen demonstrates metallic properties not that it becomes a "metal". Reversal is simple, remove it from the environment and it becomes gas and what we recognise as normal hydrogen.

Rather like Water (liquid) shows properties of a solid when below 0c.

[username]

Isn't it just that at extreme pressures and temperatures then Hydrogen demonstrates metallic properties not that it becomes a "metal". Reversal is simple, remove it from the environment and it becomes gas and what we recognise as normal hydrogen.

Rather like Water (liquid) shows properties of a solid when below 0c.

I think that it's called metallic hydrogen because at those pressures the atoms can arrange themselves in a lattice and as they only have the lattice will be surrounded by semi-dissociated electrons like the 'sea of electrons' you get in metallic lattices which get attracted by a volatge across them and the 'holes' get filled by other electrons so it can conduct electricity like a metal.

Hydrogen is just a group 1 'metal' (like sodium and potassium) which is gas at normal conditions

Metallic gases (like sodium vapour) don't conduct electricity the same way as metallic solids as the lattice doesn't exist but when you cool them they are metal again.

[RoloFanatic]

As far as i understand it Hydrogen is not actualy a metal, it is somewhere inbetween a metal and non-metal, that is why on the periodic table Hydrogen is sometimes set apart from all the other elements, or is a different colour.

Therefore, you are not really making a non-metal into a metal and so i dont think it would be possible to make a metal into a non-metal.

I hope this answeres question 2.

As for question 3, all elements at high pressure (as far as i know) become solid no matter what the temperature is, that is why the earths core is solid even though it is really hot.

Hope this helps