Nuclear Binding Energy

The energy required to break down a nucleus into its component nucleons is called the nuclear binding energy.

63Cu + Energy -- > 29 p+ + 34 no

Nuclear binding energies are usually expressed in terms of kJ/mole of nuclei or MeV's/nucleon.  Calculation of the nuclear binding energy involves the following three steps:

Determining the Mass Defect

The difference between the mass of a nucleus and the sum of the masses of the nucleons of which it is composed is called the mass defect.  Three things need to be known in order to calculate the mass defect:

To calculate the mass defect: Example:  Find the mass defect of a copper-63 nucleus if the actual mass of a copper-63 nucleus is 62.91367 amu.


Conversion of Mass Defect into Energy

To convert the mass defect into energy:

Example:  Determine the binding energy of the copper-63 atom.
(0.59223 amu/nucleus)(1.6606 x 10-27 kg/amu) = 9.8346 x 10-28 kg/nucleus
E = (9.8346 x 10-28 kg/nucleus)(2.9979 x 108 m/s)2 = 8.8387 x 10-11 J/nucleus


Expressing Nuclear Binding Energy as Energy per Mole of Atoms, or as Energy per Nucleon

The energy calculated in the previous example is the nuclear binding energy.  However, nuclear binding energy is often expressed  as kJ/mol of nuclei or as MeV/nucleon.

(8.8387 x 10-11 J/nucleus)(1 kJ/1000 J)(6.022 x 1023 nuclei/mol) = 5.3227 x 1010 kJ/mol of nuclei
(8.8387 x 10-11 J/nucleus)[1 MeV/(1.602 x 10-13 J)](1 nucleus/63 nucleons) = 8.758 MeV/nucleon


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