“Atomic fission†is when a nucleus gets hit by a neutron andsplits in half, releasing a great deal of energy. It is the basicprinciple behind nuclear reactors and nuclear weapons. The “FatMan†atomic bomb dropped on Nagasaki in 1945 had a plutonium coreof 6.4 kg of the isotope Pu-239. (Note that “239†is the molarmass.) When the bomb exploded, it released an amount of energyequivalent to 21 kilotons of TNT.
Although the bomb needed 6.4 kg of plutonium to function at all,only a portion of those plutonium atoms actually fissioned.Calculate how many kilograms of Pu-239 actually underwent fissionwhen the bomb exploded.
You will need some conversion factors to do this problem:
The energy from the explosion of 1 kiloton of TNT is equal to4.2 x 1012J.
The fission of a single atom of Pu-239 releases 210 MeV (megaelectron volts) of energy.
1 MeV = 1.602 x 10-13 J
