CONSERVATION OF MASS ENERGY - MASS DIFFERENCE
To calculate energy released or required in a nuclear reaction of any kind, we simply add all masses before and after.
Mass Difference = Total mass "before" - Total mass "after"
We can then simply convert to MeV.
Consider the nuclear collision when an alpha particle collides with N-14.The product is hydrogen and oxygen. The mass on the LHS is smaller than the RHS. Therefore energy input is required. The energy is carried by a fast alpha particle.
Mass Before Mass After
He 4.00260 H 1.00783
N 14.00307 O 16.99913
Total 18.00567 18.00696
In this case the mass AFTER reaction is greater than before! The alpha particle MUST have adequate kinetic energy for this reaction to proceed!
Mass Difference = 18.00567 - 18.00696 = - 0.00129 u
Energy required = 931 x 0.00129 MeV = 1.20 MeV
extracted from tased.com
