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Binding energy and endothermic reactions

  1. Apr 7, 2010 #1
    from masteringphyics.com,

    the binding energy of a nucleus is defined as the difference between the rest energy that the individual particles would have if they were not bound in a nucleus and the rest energy of the nucleus itself. So, stated another way, fusion reactions are exoergic if the binding energy of the product is greater than the binding energy of the original nuclei.

    i don't understand. exoergic means giving off energy, which means its exothermic reaction.
    so for exothermic reaction, the binding energy of the product has to be greater than that of reactants?

    but i thought that is for endothermic reactions? because you need to supply energy for the required binding energy in your products, which is higher than reactants?

    and issn't exothermic reaction means giving off energy, so shouldn't the energy of the products be less than the reactants since the energy is given off?
  2. jcsd
  3. Apr 7, 2010 #2


    User Avatar
    Science Advisor

    The binding energy is subtracted from the sum of the component masses to give the mass of the nucleus.
  4. Apr 7, 2010 #3


    Staff: Mentor

    Think of binding energy as a negative energy, so a greater binding energy in the products means that the products have less energy (more tightly bound) and that difference in energy is the source of the energy released.
  5. Apr 8, 2010 #4
    OH .. i see thanks!
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