An isotope of californium-252 undergoes a spontaneous fission, producing cesium-135, 3 neutrons, and one other isotope. a) Determine the identity of the other isotope produced in the fission, and write out the reaction equation, using full isotopic notation, for example Pm → C022 + Seag + 2n. b) Calculate the amount of mass (in u) lost during this fission. The masses of the three isotopes are: 252.081 626 u (californium), 134.905 978 u (cesium), 113.935 880 u (unknown). Maintain a precision of no less than 7 SF as you work. c) Calculate the energy (in MeV) released by this fission, accurate to 3 SF.

Answer :

Answer:

For a: The isotopic symbol of unknown element is [tex]_{43}^{114}\textrm{Tc}[/tex]

For b: The amount of mass lost during this process is 0.2137730 u.

For c: The energy released in the given nuclear reaction is [tex]1.99\times 10^2MeV[/tex]

Explanation:

  • For a:

In a nuclear reaction, the total mass and total atomic number remains the same.

For the given fission reaction:

[tex]^{252}_{98}\textrm{Cf}\rightarrow ^A_Z\textrm{X}+^{135}_{55}\textrm{Cs}+3^1_0\textrm{n}[/tex]

  • To calculate A:

Total mass on reactant side = total mass on product side

252 = A + 135 + 3

A = 114

  • To calculate Z:

Total atomic number on reactant side = total atomic number on product side

98 = Z + 55 + 0

Z = 43

Hence, the isotopic symbol of unknown element is [tex]_{43}^{114}\textrm{Tc}[/tex]

  • For b:

We are given:

Mass of [tex]_{98}^{252}\textrm{Cf}[/tex] = 252.081626 u

Mass of [tex]_{0}^{1}\textrm{n}[/tex] = 1.008665 u

Mass of [tex]_{55}^{135}\textrm{Cs}[/tex] = 134.905978 u

Mass of [tex]_{43}^{114}\textrm{Tc}[/tex] = 113.935880 u

To calculate the mass defect, we use the equation:

[tex]\Delta m=\text{Mass of reactants}-\text{Mass of products}[/tex]

Putting values in above equation, we get:

[tex]\Delta m=(m_{Cf})-(m_{Cs}+m_{Tc}+3m_{n})\\\\\Delta m=(252.081626)-(134.905978+113.935880+3(1.008665))=0.2137730u[/tex]

Hence, the amount of mass lost during this process is 0.2137730 u.

  • For c:

To calculate the energy released, we use the equation:

[tex]E=\Delta mc^2\\E=(0.2137730u)\times c^2[/tex]

[tex]E=(0.2137730u)\times (931.5MeV)[/tex] (Conversion factor:  [tex]1u=931.5MeV/c^2[/tex]  )

[tex]E=1.99\times 10^2MeV[/tex]

Hence, the energy released in the given nuclear reaction is [tex]1.99\times 10^2MeV[/tex]

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