Chapter 19, Problem 36A

Interpretation Introduction

Interpretation: A balance equation of reaction between $U$ and neutrons needs to be determined.

Concept introduction: Nuclear fission is a process by which the nucleus of a heavier atom is split into two or more smaller nuclei generally by the bombardment of neutrons. The reaction is exothermic and huge amounts of energy are released in the process.

Answer to Problem 36A

The balanced equation: ${}_{\text{ 92}}^{\text{ 235}}U+{}_0^{\text{1}}n\to {}_{56}^{140}Ba+{}_{36}^{93}Kr+{\text{ 3}}_0^{\text{1}}n$

Explanation of Solution

Example of nuclear fission:

  ${}_{\text{ 92}}^{\text{ 235}}U+{}_0^{\text{1}}n\to {}_{56}^{140}Ba+{}_{36}^{93}Kr+{\text{ 3}}_0^{\text{1}}n$

Fission of Uranium (heavier nucleus) occurs to form Barium and Krypton (lighter nucleus).

In balance a nuclear equation, the atomic numbers and mass number of all species on either side of the arrow must be equal.

Total atomic number on right side of the equation is $=56+36+3\times 0=92$

Total atomic number on left side of the equation is $=92+0=92$

Total mass number on right side of the equation is $=140+93+3\times 1=236$

Total mass number on left side of the equation is $=235+1=236$

So, both atomic numbers and mass number are perfectly balanced in the nuclear equation.

Conclusion

The balanced equation: ${}_{\text{ 92}}^{\text{ 235}}U+{}_0^{\text{1}}n\to {}_{56}^{140}Ba+{}_{36}^{93}Kr+{\text{ 3}}_0^{\text{1}}n$