Calculate the binding energy (in J) and the nuclear binding energy per nucleon of (82.9152 amu).?

Question

Sorry the element is Br
atomic number=35
atomic mass=83

Answer 1

If you add up the mass of 35 protons and 48 neutrons (=83 particles in the nucleus), guess what? It is greater than 82.9152 (Note: it is acceptable to *not* count electron mass, because it is negligible).

Add it up and see!:
35 * 1.008142 amu = 35.285 amu (protons)
plus
48 * 1.008982 amu = 48.4311 amu (neutrons)
equals
83.7161 amu

(you can look those weights for proton & neutron up, in your textbook)

OK, so where did all that energy go? into Binding energy.
The difference is 83.7161 - 82.9152 = 0.8009 amu

To get from atomic mass units (amu) to Energy in Joules, use Einsteins famous equation E = mc^2 (or look up the conversion factor from amu to Joules in a conversion table).

amu must be converted to kilograms first
1 amu = 1.657*10^-27 kg

E = (1.657*10^-27 kg/amu * 0.8009 amu) * (8.99*10^16)
E = 1.193*10^-10 Joules

***Don't forget to divide by 83 to get the energy PER nucleon, because that 1.193e-27 number is the *total* binding energy.


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