Nuclear Fission Basics: Calculating Energy Released U-235

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The discussion revolves around calculating the energy released during the fission of a U-235 nucleus, focusing on the mass-energy equivalence principle as described by Einstein's equation, E=mc². Participants are analyzing the mass differences between the original nucleus and the resulting decay products.

Discussion Character

  • Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to calculate energy using the mass of a neutron but questions the validity of their result. Another participant suggests calculating the mass difference between U-235 and the decay products, leading to a different energy calculation. There is also a mention of typical energy values associated with U-235 fission.

Discussion Status

The discussion includes various calculations and attempts to verify the correctness of energy values derived from mass differences. Some participants express uncertainty about their results, while others provide typical energy values for context, indicating a mix of exploration and verification.

Contextual Notes

Participants are working within the constraints of given particle masses and are exploring the implications of different decay products on energy calculations. There is an acknowledgment that typical fission outcomes can vary based on specific reactions.

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calculate the amount of energy released in the fission of a U-235 nucleus.
http://www.dummies.com/WileyCDA/DummiesArticle/Nuclear-Fission-Basics.id-1669.html
Given:
Masses of the particles:
U-235 = 234.9993u
n=1.008
Ba=140.883u
Kr=91.905u

what i did was i used delta E=mc^2, where m is the mass of n...which is 1.008.. and i get 1.5x10^-10... why is this wrong?/
 
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The energy given off is the mass difference between the original U and the total of the decay products.

U235 = 234.9993
Ba+Kr+n=140.883+91.905+1.008 = 233.796
difference = 1.203 then just E=mc^2
 
thanks:)
 
delta E=1.795x10^-10J...is this answer correct?
 
i got it:)...the answer is 2.82x10^-11J.
 
If you did the arithmetic correctly!
Typical U235 fission is around 200Mev or 3E-11J but depends on the exact breakup products
with U235->Ba + Kr you would normally get 2 'extra' neutrons so your free energy is only about 0.2u
 

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