High School

Dear beloved readers, welcome to our website! We hope your visit here brings you valuable insights and meaningful inspiration. Thank you for taking the time to stop by and explore the content we've prepared for you.
------------------------------------------------ In a particular fission of a uranium-235 ([tex]^{235}U[/tex]) nucleus, which has a neutral atomic mass of 235.0439 u, a reaction energy of 200 MeV is released.

(a) A mass of 1.00 kg of pure uranium-235 contains how many atoms?

(b) How much total energy is released if the entire mass of 1.00 kg of uranium-235 fissions?

(c) Suppose that these fission reactions occur at a rate to release a constant 100 W of power to a lamp for a long period of time. Assuming 100% of the reaction energy goes into powering the lamp, for how many years can the lamp run?

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

#SPJ11