NUCLEAR FISSION A process of splitting of a heavy nucleus into two lighter nuclei The heavy nucleus is bombarded by a neutron At end of the process,it produces ; Two new nuclei Three neutrons Nuclear energy

NUCLEAR FISSION Uranium-235 neutron

NUCLEAR FISSION

NUCLEAR FISSION 2 new nuclei,3 neutrons and energy produced

NUCLEAR FISSION Barium-141 neutron neutron neutron Uranium-235 neutron Krypton-92

U Kr Ba n NUCLEAR FISSION NUCLEAR FISSION EQUATION + 3 + energy 235 92 Kr 36 Ba 141 56 n 1 + 3 + energy EXERCISE Calculate the nuclear energy produced in the nuclear fission above in Joule and eV. Uranium-235 = 235.04 a.m.u Krypton-92 = 91.93 a.m.u Barium-141 = 140.91 a.m.u Neutron = 1.01 a.m.u 2.69 x 10-11 J

U Kr Ba n NUCLEAR FISSION NUCLEAR FISSION EQUATION + 3 + energy 235 92 Kr 36 Ba 141 56 n 1 + 3 + energy Mass defect = mass before – mass after = [235.04 + 1.01] – [140.91 + 91.93 + 3(1.01)] = 0.18 a.m.u = 0.18 x 1.66 x 10-27 kg = 2.988 x 10-28 kg E = mc2 = 2.988 x 10-28 x (3.0 x 108)2 = 2.69 x 10-11 J = 1.68 x 108 eV

NUCLEAR FISSION CHAIN REACTION A chain reaction occurs when a further nuclear fission is continuously occurred. This is happen when the neutron which is produced in earlier nuclear fission bombarding the new nuclei. Again,the process will produce 2 new nuclei,3 neutron and nuclear energy. Chain reaction only can happen when the mass of uranium is exceeded the critical mass.

NUCLEAR FISSION CHAIN REACTION neutron

NUCLEAR FISSION CHAIN REACTION neutron

PAST YEARS QUESTION A. 3.22 x 10-28 kg B. 9.67 x 10-20 kg C. In the fission reaction for an atom of uranium-235,the energy produced is 2.9 x 10-11 J.What is the total loss of mass in the reaction ? A. 3.22 x 10-28 kg E = mc2 2.9 x 10-11 = m x (3 x 108)2 B. 9.67 x 10-20 kg m = 3.22 x 10-28 kg C. 2.61 x 106 kg D. 1.03 x 1019 kg

PAST YEARS QUESTION a. What is meant by nuclear fission ? A process of splitting a heavy nucleus into two lighter nuclei b. What is meant by nuclear fusion ? A process of combining two heavy nuclei to form a heavier nucleus

PAST YEARS QUESTION c. Using the information in the table,compare the nuclear fission and nuclear fusion.Hence state the relationship between mass and energy evolved. 1. Nuclear fission is a process of splitting a heavy nucleus to lighter nuclei while nuclear fusion is a process of combining light nuclei to heavier nucleus 2. Both reactions release nuclear energy 3. Nuclear energy released due to mass loss

PAST YEARS QUESTION Describe how the chain reaction happens in a nuclear fission of an atom of uranium. neutron Heavy nucleus 3 neutrons Heavy nucleus is bombarded by neutron Heavy nucleus Two lighter nuclei and three neutron are produced Light nucleus Neutron continue to hit the new nuclei and produce two lighter nuclei and three neutron