Answer :
A particular fission of a uranium-235 (235 U) nucleus, which has neutral atomic mass 235.0439 u, a reaction energy of 200 MeV is released.(a)1.00 kg of pure uranium contains approximately 2.56 x 10^24 uranium-235 atoms.(b)the total energy released if the entire mass of 1.00 kg of uranium-235 undergoes fission is approximately 3.11 x 10^13 joules.(c)assuming 100% of the reaction energy goes into powering the lamp, the lamp can run for approximately 983,544 years.
(a) To determine the number of uranium-235 (235U) atoms in 1.00 kg of pure uranium, we need to use Avogadro's number and the molar mass of uranium-235.
Calculate the molar mass of uranium-235 (235U):
Molar mass of uranium-235 = 235.0439 g/mol
Convert the mass of uranium to grams:
Mass of uranium = 1.00 kg = 1000 g
Calculate the number of moles of uranium-235:
Number of moles = (Mass of uranium) / (Molar mass of uranium-235)
Number of moles = 1000 g / 235.0439 g/mol
Use Avogadro's number to determine the number of atoms:
Number of atoms = (Number of moles) × (Avogadro's number)
Now we can perform the calculations:
Number of atoms = (1000 g / 235.0439 g/mol) × (6.022 x 10^23 atoms/mol)
Number of atoms ≈ 2.56 x 10^24 atoms
Therefore, 1.00 kg of pure uranium contains approximately 2.56 x 10^24 uranium-235 atoms.
(b) To calculate the total energy released if the entire mass of 1.00 kg of uranium-235 undergoes fission, we need to use the energy released per fission and the number of atoms present.
Given:
Reaction energy per fission = 200 MeV (mega-electron volts)
Convert the reaction energy to joules:
1 MeV = 1.6 x 10^-13 J
Energy released per fission = 200 MeV ×(1.6 x 10^-13 J/MeV)
Calculate the total number of fissions:
Total number of fissions = (Number of atoms) × (mass of uranium / molar mass of uranium-235)
Multiply the energy released per fission by the total number of fissions:
Total energy released = (Energy released per fission) × (Total number of fissions)
Now we can calculate the total energy released:
Total energy released = (200 MeV) * (1.6 x 10^-13 J/MeV) × [(2.56 x 10^24 atoms) × (1.00 kg / 235.0439 g/mol)]
Total energy released ≈ 3.11 x 10^13 J
Therefore, the total energy released if the entire mass of 1.00 kg of uranium-235 undergoes fission is approximately 3.11 x 10^13 joules.
(c) To calculate the number of years the lamp can run, we need to consider the power generated by the fission reactions and the total energy released.
Given:
Power generated = 100 W
Total energy released = 3.11 x 10^13 J
Calculate the time required to release the total energy at the given power:
Time = Total energy released / Power generated
Convert the time to years:
Time in years = Time / (365 days/year ×24 hours/day ×3600 seconds/hour)
Now we can calculate the number of years the lamp can run:
Time in years = (3.11 x 10^13 J) / (100 W) / (365 days/year × 24 hours/day * 3600 seconds/hour)
Time in years ≈ 983,544 years
Therefore, assuming 100% of the reaction energy goes into powering the lamp, the lamp can run for approximately 983,544 years.
To learn more about Avogadro's number visit: https://brainly.com/question/859564
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