# Energy released when splitting H2

• jaketodd
In summary, the amount of energy released from splitting a single H2 molecule's nucleus depends on the specific isotope and the process used. For example, splitting the nucleus of deuterium (2H) or tritium (3H) can release significant amounts of energy through nuclear fusion. On the other hand, splitting the more common isotope of hydrogen, 1H, usually requires energy to be put in. For an arbitrary atom, the energy released from splitting the nucleus can be calculated using the liquid drop model. In the case of uranium-235, about one-tenth of 1 percent of its mass is converted to energy of ~200 MeV. The amount of energy released from splitting deuterium or hydrogen-
jaketodd
Gold Member
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

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

jaketodd said:
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).

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.

Jake

Last edited:
jaketodd said:
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.

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.

edguy99 said:
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

jaketodd said:
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.

Last edited by a moderator:
edguy99 said:
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.

Last edited by a moderator:
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

Drakkith said:
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

jaketodd said:
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

Last edited:
jaketodd said:
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.

## 1. What is the process of splitting H2 and what causes energy to be released?

The process of splitting H2, also known as hydrogen splitting or hydrogen dissociation, involves breaking the chemical bonds between the two hydrogen atoms in a molecule of H2. This process is typically initiated by the input of energy, and the resulting energy released is due to the breaking of these bonds.

## 2. How much energy is released when splitting H2?

The amount of energy released when splitting H2 can vary depending on the specific conditions and methods used. However, on average, it takes about 436 kJ/mol of energy to break the bonds in H2, resulting in the release of the same amount of energy.

## 3. Can the energy released from splitting H2 be harnessed for practical use?

Yes, the energy released from splitting H2 can be harnessed for various practical uses. For example, it can be used to power fuel cells, which convert the energy from hydrogen into electricity. It can also be used in combustion engines to power vehicles and in industrial processes for heating and electricity generation.

## 4. Is splitting H2 a sustainable source of energy?

Splitting H2 can be considered a sustainable source of energy if it is produced using renewable energy sources, such as solar or wind power. This is because the energy used to produce H2 is not derived from fossil fuels and does not contribute to greenhouse gas emissions.

## 5. Are there any environmental concerns associated with splitting H2?

While splitting H2 itself does not produce harmful emissions, the production of H2 through steam reforming or other methods can contribute to greenhouse gas emissions and air pollution. Additionally, the production and transportation of H2 can also have environmental impacts. Therefore, it is important to consider the source of the energy used to produce H2 and the methods used in its production to mitigate potential environmental concerns.

Replies
5
Views
1K
Replies
10
Views
2K
Replies
10
Views
2K
Replies
10
Views
2K
Replies
3
Views
2K
Replies
8
Views
1K
Replies
14
Views
2K
Replies
1
Views
1K
Replies
4
Views
2K
Replies
29
Views
2K