Nuclear Reaction
Definition and meaning of Nuclear Reaction in chemistry.
A nuclear reaction is a process in which two nuclei or a nucleus and a subatomic particle collide and transform into different nuclei or particles. These reactions differ fundamentally from chemical reactions because they involve the nucleus and can transmute one element into another.
In more detail
Nuclear reactions are governed primarily by the strong nuclear force, though certain processes such as beta decay are instead mediated by the weak nuclear force. These reactions release or absorb energy according to E=mc2, where the energy derives from the conversion of mass. They occur naturally through radioactive decay and can also be induced in laboratories. All nuclear reactions conserve both mass number and atomic number. The most energetically significant types are fission (a nucleus splitting) and fusion (nuclei combining), which power nuclear reactors and stars, respectively.
Key facts
| Field | Physical Chemistry |
|---|---|
| Example reaction | U-235 + neutron → Ba-141 + Kr-92 + 3 neutrons |
| Energy source | mass converted to energy via E=mc2 |
| Governing force | strong and weak nuclear forces, depending on the process |
When uranium-235 absorbs a neutron, it undergoes fission, producing barium-141 and krypton-92 while releasing three neutrons and approximately 200 million electron volts of energy.
Frequently asked questions
How does a nuclear reaction differ from a chemical reaction?
Nuclear reactions involve the nucleus and can change elements, while chemical reactions only involve electrons and preserve elements. Nuclear reactions release millions of times more energy.
What conservation laws apply to nuclear reactions?
The mass number (total nucleons) and atomic number (total protons) must be equal before and after the reaction, ensuring charge and nucleon conservation.