Nuclear Chemistry

 

 

Nuclear chemistry deals with the study of nuclear particles, nuclear forces and nuclear reactions. This field began with the discovery of radioactivity.  A good deal of knowledge was accumulated during the next few decades and thus led to the discovery of artificial radioactivity. The release of tremendous amount of energy through nuclear reactions became possible with the development of artificial radioactivity. Nuclear chemistry,  therefore,  constitutes an important  branch of science. The release of nuclear energy holds out great hope for the future as the present natural resources of energy are fast approaching exhaustion.

Nuclear fission 

O.hahn and F strassmann observed during 1934 to 1938 that when uranium 235 is bombarded with slow moving neutrons, it undergoes fission giving barium and krypton as the products of  fission. In order to explain this observation ,it was suggested that after the capture of a neutron, the uranium nucleus gets excited and them splits into two fragments of approximately equal mass.

The splitting of a heavy nucleus into two smaller fragments of approximately equal mass is known as nuclear fission. 

The fission products are, in fact, radioactive themselves . They are rich in neutrons and decay by emitting beta particles, or neutrons,  gamma radiation and ultimately change into stable elements. The energy released in one fission reaction is different from the energy released from other fission reaction. The number of neutrons released also varies from one fission reaction to another. But on an average approximately 200MeV energy and 2 5 neutrons are released in the fission of an atom of uranium 235.

Fact: Nearly 50 modes of fission reactions of uranium 235 are known.

 Binding energy: The energy released in the formation of a nucleus from its constituent nucleons.

More binding energy means more energy will be required to break the nucleus that means nucleus is stable. 

Nuclear fusion 

A reaction in which two lighter nuclei combine to form a heavier nucleus accompanied by release of energy is called nuclear fusion. Since the nuclei are charged and repel.each other, the fusion can occur only by  making on nucleus collide with another highly energetically  i.e the kinetic energy of each nucleus should be kept very highso that it  overcomes the repulsive forces i.e repulsive coulombic potentia energy barrier between them. Since kinetic energy needed to overcome the coulombic repulsion increases rapidly with the atomic number , the lighter the nuclei  the greater the chance for them to approach closely. Thus, the hydrogen isotopes are best candidates for bringing about nuclear fusion.

Such process occur at reasonable rates only at very high temperatures, of the order of millions of degree centigrade. Once a fusion is initiated , the energy released is sufficient to maintain the temperature and to keep the process going.

Thus fusion and fission are the future of energy production, Which is clean and provide high amount of energy from small quantities of sources.