Nuclear Fission Basics: Calculating Energy Released U-235

In summary, the amount of energy released in the fission of a U-235 nucleus can be calculated using the formula delta E=mc^2, where m is the mass difference between the original U-235 and the total of the decay products. The typical energy released is around 200Mev or 3E-11J, depending on the exact breakup products.
  • #1
rojasharma
66
0
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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  • #2
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
 
  • #3
thanks:)
 
  • #4
delta E=1.795x10^-10J...is this answer correct?
 
  • #5
i got it:)...the answer is 2.82x10^-11J.
 
  • #6
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
 

1. What is nuclear fission and how does it work?

Nuclear fission is a process in which the nucleus of an atom is split into two or more smaller nuclei. This process releases a large amount of energy, which can be harnessed for various purposes. In the case of U-235, the nucleus is split by absorbing a neutron, which causes it to become unstable and split into two smaller nuclei, releasing more neutrons and energy in the process.

2. How is the energy released from U-235 calculated?

The energy released from U-235 can be calculated using the equation E=mc², where E is energy, m is mass, and c² is the speed of light squared. In this equation, the mass is the difference between the mass of the initial U-235 atom and the combined mass of the resulting nuclei and neutrons. This energy is typically measured in megaelectronvolts (MeV).

3. What factors affect the energy released from U-235 during fission?

The amount of energy released from U-235 during fission can be affected by several factors, including the speed of the neutron, the size of the uranium nucleus, and the presence of other elements or isotopes. The energy released can also vary depending on the specific reaction and the materials used to contain and moderate the fission process.

4. What is the significance of U-235 in nuclear fission?

U-235 is one of the isotopes of uranium that is capable of undergoing nuclear fission. It is an important fuel source for nuclear power plants and weapons due to its high concentration of fissile material and its ability to sustain a chain reaction. However, it is also highly unstable and must be carefully handled to prevent accidents or explosions.

5. What are the potential dangers of U-235 fission?

The potential dangers of U-235 fission include radiation exposure, nuclear accidents, and the production of nuclear waste. If not properly controlled, the fission process can release harmful radiation into the environment, causing health risks for humans and other living organisms. Additionally, the disposal of nuclear waste from fission reactions is a complex and ongoing issue that has significant environmental and health implications.

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