Energy released when splitting H2

[jaketodd]

I would greatly appreciate anyone who can tell me reliably how much energy is released from splitting a single H2 molecule's nucleus.

Thanks,

Jake

 

[Drakkith]

H2 as in a Hydrogen-Hydrogen molecule, or an atom of Deuterium? You have "single H2 molecules nucleus" up there which is confusing.

 

[SpectraCat]

I would greatly appreciate anyone who can tell me reliably how much energy is released from splitting a single H2 molecule's nucleus.

Thanks,

Jake

That question doesn't really make sense for a number of reasons:

1) An H₂ *molecule* is composed of two covalently bonded atoms, so there is more than one nucleus associated with it.

2) By far, the most common isotope of hydrogen is ¹H, and the nucleus of such an atom is just a proton. The only way to "split" a proton is in a cyclotron "atom-smasher" or similar apparatus, which I guess is not what you are asking about (but see [*] below).

3) Finally, usually when one talks about splitting a nucleus, especially a low-mass nucleus, one is talking about a process that requires energy. Some larger nuclei can be split by nuclear fission, either spontaneously or (more commonly) when impacted by a sufficiently energetic neutron. Such fission processes can release a lot of energy, but are generally restricted to heavier isotopes, such as U-235, P-239 and other actinides.

Anyway, while that doesn't really answer your question .. hopefully it clarifies things somewhat.[*] If you are talking about heavy isotopes of hydrogen (i.e. deuterium, or ²H, and tritium, or ³H), then it is possible to split those atoms. Tritium is unstable with a half-life of a few years, and undergoes spontaneous beta-decay to form helium-3. Deuterium is stable, but the neutron can be split off if you put in sufficient energy. That process can ultimately release A LOT of energy under the appropriate circumstances (c.f. D+D nuclear fusion).

 

[jaketodd]

I see what you mean... Let me revise the question: Please give me an example of a simple atom and provide the energy released when the nucleus is split.

Thanks for your patience,

Jake

 

[edguy99]

I see what you mean... Let me revise the question: Please give me an example of a simple atom and provide the energy released when the nucleus is split.

Thanks for your patience,

Jake

The bond strength for one proton and one neutron (Deuterium or Hydrogen2) is about 1.1MeV. Ie. 1.1MeV of energy will be released if the nucleus is split.

 

[jaketodd]

The bond strength for one proton and one neutron (Deuterium or Hydrogen2) is about 1.1MeV. Ie. 1.1MeV of energy will be released if the nucleus is split.

Thank you! How do you calculate that for an arbitrary atom??

Jake

 

[edguy99]

Thank you! How do you calculate that for an arbitrary atom??

Jake

http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/liqdrop.html#c2".

Sorry, but I also just noticed that my prior answer of 1.1MeV was per nucleon. I answered your question backwards. 2.2MeV of energy would be required to split them. 2.2MeV of energy would be released if they were forcibly joined together.

 

[jaketodd]

http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/liqdrop.html#c2".

Sorry, but I also just noticed that my prior answer of 1.1MeV was per nucleon. I answered your question backwards. 2.2MeV of energy would be required to split them. 2.2MeV of energy would be released if they were forcibly joined together.

Thanks but I am looking for energy released when a nucleus is split. Can you or anyone tell me how to figure out how much energy is released when an atom's nucleus is broken up? An example would be great.

 

[Drakkith]

From wikipedia:

When a uranium nucleus fissions into two daughter nuclei fragments, about one-tenth of 1 percent of the mass of the uranium nucleus[4] is converted to energy of ~200 MeV. For uranium-235 (total mean fission energy 202.5 MeV), typically ~169 MeV appears as the kinetic energy of the daughter nuclei, which fly apart at about 3% of the speed of light, due to Coulomb repulsion. Also, an average of 2.5 neutrons are emitted with a kinetic energy of ~2 MeV each (total of 4.8 MeV). The fission reaction also releases ~7 MeV in prompt gamma ray photons. The latter figure means that a nuclear fission explosion or criticality accident emits about 3.5% of its energy as gamma rays, less than 2.5% of its energy as fast neutrons (total ~ 6%), and the rest as kinetic energy of fission fragments ("heat"). In an atomic bomb, this heat may serve to raise the temperature of the bomb core to 100 million kelvin and cause secondary emission of soft X-rays, which convert some of this energy to ionizing radiation. However, in nuclear generators, the fission fragment kinetic energy remains as low-temperature heat which causes little or no ionization.

See here: http://en.wikipedia.org/wiki/Nuclear_fission

 

[jaketodd]

From wikipedia:

When a uranium nucleus fissions into two daughter nuclei fragments, about one-tenth of 1 percent of the mass of the uranium nucleus[4] is converted to energy of ~200 MeV. For uranium-235 (total mean fission energy 202.5 MeV), typically ~169 MeV appears as the kinetic energy of the daughter nuclei, which fly apart at about 3% of the speed of light, due to Coulomb repulsion. Also, an average of 2.5 neutrons are emitted with a kinetic energy of ~2 MeV each (total of 4.8 MeV). The fission reaction also releases ~7 MeV in prompt gamma ray photons. The latter figure means that a nuclear fission explosion or criticality accident emits about 3.5% of its energy as gamma rays, less than 2.5% of its energy as fast neutrons (total ~ 6%), and the rest as kinetic energy of fission fragments ("heat"). In an atomic bomb, this heat may serve to raise the temperature of the bomb core to 100 million kelvin and cause secondary emission of soft X-rays, which convert some of this energy to ionizing radiation. However, in nuclear generators, the fission fragment kinetic energy remains as low-temperature heat which causes little or no ionization.

See here: http://en.wikipedia.org/wiki/Nuclear_fission

Thanks, but I am now wondering how much energy is released from Deuterium/Hydrogen2 when its nucleus is split. Does anyone know this one?

Thanks!

Jake

 

[SpectraCat]

Thanks, but I am now wondering how much energy is released from Deuterium/Hydrogen2 when its nucleus is split. Does anyone know this one?

Thanks!

Jake

None .. see edguy99's last post.

[EDIT] or even my first response to you for an alternative answer

 

[Drakkith]

Thanks, but I am now wondering how much energy is released from Deuterium/Hydrogen2 when its nucleus is split. Does anyone know this one?

Thanks!

Jake

The nucleus for Deuterium has a binding energy which can be released only through fusion, not fission.