 Since binding energy is so closely related to mass, we can trivially evaluate the energy released in reactions by using the binding energies of the products in the reactants. Let's again look at the curve of binding energy per nucleon and use it to estimate the energy emitted when uranium-235 undergoes fission. We know already that uranium-235 tends to break into asymmetric products, and here we consider the case where two fragments are created with nucleon numbers of 140 and 95 respectively. We can estimate the binding energy per nucleon for each of the target and the two fission fragments by drawing some lines on the graph. We end up getting the values listed here, and hence we can estimate the energy released in the fission of uranium-235 by looking at the difference in the binding energies. Thus we predict that approximately 181 MeV of energy will be released from every uranium-235 atom that splits, and this number agrees quite well with the value produced from the actual masses in earlier lectures. The key point to be taken from this example is that the slope of the binding energy per nucleon curve means that the break-up of having nuclei into lighter fragments is often energy favoured. It should also be obvious from the behaviour of the binding energies of light nuclei that an equivalent energy release should be possible when light nuclei fuse together.