Which equation represents a fission reaction?
${ }_7^{14} N+{ }_1^1 H \longrightarrow{ }_8^{15} O$
${ }_{92}^{235} U +{ }_0^1 n \longrightarrow{ }_{55}^{140} Cs +{ }_{37}^{94} Rb +2_0^1 n$
${ }_4^9 Be +{ }_2^4 He \longrightarrow{ }_6^{12} C +{ }_0^1 n$
${ }_{93}^{239} Np \longrightarrow{ }_{94}^{239} Pu +{ }_{-1}^0 e$
Answer (1)
Fission involves a heavy nucleus splitting into lighter nuclei.
The reaction 92 235 U + 0 1 ni g h t ha r p oo n u p 55 140 C s + 37 94 R b + 2 0 1 n shows Uranium-235 splitting into Cesium-140 and Rubidium-94.
Other reactions involve combining light nuclei or radioactive decay.
Therefore, the fission reaction is 92 235 U + 0 1 ni g h t ha r p oo n u p 55 140 C s + 37 94 R b + 2 0 1 n .
Explanation
Understanding Fission We need to identify which of the given nuclear reactions represents a fission reaction. Fission is characterized by a heavy nucleus splitting into lighter nuclei. Let's analyze each option.
Analyzing Reaction 1 The first reaction is: 7 14 N + 1 1 H i g h t ha r p oo n u p 8 15 O . This reaction involves two light nuclei combining to form a heavier nucleus. This is a fusion reaction, not fission.
Analyzing Reaction 2 The second reaction is: 92 235 U + 0 1 ni g h t ha r p oo n u p 55 140 C s + 37 94 R b + 2 0 1 n . Here, a heavy nucleus (Uranium-235) absorbs a neutron and splits into two lighter nuclei (Cesium-140 and Rubidium-94) and releases more neutrons. This is a fission reaction.
Analyzing Reaction 3 The third reaction is: 4 9 B e + 2 4 He i g h t ha r p oo n u p 6 12 C + 0 1 n . This reaction involves two light nuclei combining to form a heavier nucleus. This is not fission.
Analyzing Reaction 4 The fourth reaction is: 93 239 Np i g h t ha r p oo n u p 94 239 P u + − 1 0 e . In this reaction, a heavy nucleus decays into another heavy nucleus and an electron. This is a radioactive decay, not fission.
Conclusion Therefore, the equation that represents a fission reaction is the second one: 92 235 U + 0 1 ni g h t ha r p oo n u p 55 140 C s + 37 94 R b + 2 0 1 n .
Examples
Fission reactions are used in nuclear power plants to generate electricity. The energy released from the splitting of uranium atoms heats water, which creates steam to turn turbines and produce electricity. Understanding fission is crucial for developing and managing nuclear energy resources, as well as for understanding the dangers and applications of nuclear weapons.
