Energy change in a nuclear reaction

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SUMMARY

The discussion centers on the energy change during the nuclear reaction where a fluorine-18 nucleus captures a proton to form a neon-19 nucleus. The calculated energy change is 6.5 MeV, indicating that energy is released rather than absorbed. This conclusion is drawn from the analysis of mass defects, where the mass defect of fluorine-18 is 0.14712 u and that of neon-19 is 0.15398 u, leading to an increase in mass defect and a corresponding release of energy to conserve total energy. The key takeaway is that the mass of the products is less than that of the reactants, confirming energy release.

PREREQUISITES
  • Understanding of nuclear reactions and mass defect
  • Familiarity with Einstein's mass-energy equivalence principle (E = mc²)
  • Knowledge of binding energy concepts in nuclear physics
  • Basic grasp of isotopes, specifically fluorine-18 and neon-19
NEXT STEPS
  • Research the concept of binding energy in nuclear physics
  • Learn about the process of proton capture in nuclear reactions
  • Explore the implications of mass defect in various nuclear reactions
  • Study the application of E = mc² in calculating energy changes in nuclear processes
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Students studying nuclear physics, educators teaching nuclear reactions, and researchers interested in energy changes associated with nuclear transformations.

songoku
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Homework Statement
A fluorine - 18 nucleus can capture proton producing a neon - 19 nucleus as the product. The mass defect of fluorine - 18 and neon - 19 are 0.14712 u and 0.15398 u respectively. What is the energy change associated with this reaction?
Relevant Equations
E = mc^2
I got 6.5 MeV but I don't understand how to determine whether the energy is released or absorbed. My guess: the energy is absorbed because mass defect of neon is bigger?

Thanks
 
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songoku said:
Homework Statement:: A fluorine - 18 nucleus can capture proton producing a neon - 19 nucleus as the product. The mass defect of fluorine - 18 and neon - 19 are 0.14712 u and 0.15398 u respectively. What is the energy change associated with this reaction?
Homework Equations:: E = mc^2

I got 6.5 MeV but I don't understand how to determine whether the energy is released or absorbed. My guess: the energy is absorbed because mass defect of neon is bigger?

Thanks
What is your understanding of how mass defect is defined?
 
haruspex said:
What is your understanding of how mass defect is defined?

Difference between total mass of products and parents because some of the masses are converted to energy
 
songoku said:
Difference between total mass of products and parents because some of the masses are converted to energy
That's ambiguous because a difference is unsigned, and when given as the mass defect of an atom it is not in respect of an arbitrary disassemblage. Can you be more precise?
 
I think the more appropriate definition of mass defect is the total mass of proton and neutron minus mass of the nuclei
 
songoku said:
I think the more appropriate definition of mass defect is the total mass of proton and neutron minus mass of the nuclei
Right, so has the mass defect (of the whole system) increased or decreased? What does that mean about the change in total mass?
 
haruspex said:
Right, so has the mass defect (of the whole system) increased or decreased? What does that mean about the change in total mass?
The mass defect of the system increases so the total mass also increases. This means that Ne has higher binding energy than F so some energy must be released to keep the energy conserved?

Thanks
 
songoku said:
The mass defect of the system increases so the total mass also increases.
A defect is a shortage. If I have a shortage of cash for something I want to buy and the shortage increases, do I have more cash or less?
 
haruspex said:
A defect is a shortage. If I have a shortage of cash for something I want to buy and the shortage increases, do I have more cash or less?
Oh ok so since the shortage increases it means that mass of the product is less compared to mass of reactants so some of mass of reactants is converted to energy and released through the process
 
  • #10
songoku said:
Oh ok so since the shortage increases it means that mass of the product is less compared to mass of reactants so some of mass of reactants is converted to energy and released through the process
Yes.
 
  • #11
Thank you very much
 

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