Where does the energy from Nuclear Fission comes from?

1. Feb 11, 2010

Leronira

Looking at the fission of Uranium 235, the typical end product will be Barium 141 and Krypton 92, and 3 neutrons.
From this, we can calculate the energy that the fission gives off, by taking the difference in mass of the product and "reactant", and use the equation of E=mc2.
But what i see from the above, there isn't any difference in mass. Or am I missing out something here? Someone enlighten me please. Thanks

2. Feb 11, 2010

Matterwave

There is a difference in mass, just a very small one...for these calculations, you can not use the usual approximation that mass is just number of protons plus number of neutrons.
235.0439299-140.914411-91.926156-2(1.0086649)=.186amu

In energy this is equivalent to 173MeV which is around the 200MeV usually released by U-235 decay.

3. Feb 11, 2010

Leronira

OHH...so i have to look all the way down to many decimal places inorder to see the difference in mass...ok..thanks alot...=D