Question

When a neutron (n) collides with a uranium-235 nucleus it can induce a variety of fission reactions. One such reaction is U + n → Xe + Sr + 2n. How much energy is released in this reaction, given the following mass values: Xe: 139.921620 u Sr : 93.915367 u U: 235.043924 u n: 1.008665 u (1 u = 931.494 MeV/c2)

Answer 1

Explanation:

Since, the given reaction is $U + n \rightarrow Xe + Sr + 2n$

Sum of masses on both reactant and product side is as follows.

           235.043924 + 1.008665 = 139.921620 + 93.915367 + (2 × 1.008665)

                            = 0.198272 u

As it is known that relation between energy and mass is as follows.

                   Energy produced = $\Delta m c^{2}$

Since, 1 u = 931.494 MeV/$c^{2}$. Putting this value into the above formula as follows.

                   Energy produced = $\Delta m c^{2}$

                                                  = $0.198272 \times \frac{931.494}{c^{2}} \times c^{2}$

                                                   = 184.69 MeV

As 1 MeV equals $1.602 \times 10^{-13}$ joules.

Hence, 184.69 MeV will be converted into joules as follows.

            $184.69 MeV \times \frac{1.602 \times 10^{-13}J}{1 MeV}$

                  = $295.87 \times 10^{-13}$ J

                  = $2.95 \times 10^{-17}$ J

Thus, we can conclude that energy released in this reaction is $2.95 \times 10^{-15}$ J.