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Download Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

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  • Slide 1
  • Nuclear Chemistry Fusion and Fission
  • Slide 2
  • Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60) tend to break into smaller atoms, thereby increasing their stability. Nuclear fission releases a large amount of energy.
  • Slide 3
  • Nuclear Fission
  • Slide 4
  • U 235 92 n 1 0 The Fission Process A neutron travels at high speed towards a uranium-235 nucleus.
  • Slide 5
  • U 235 92 n 1 0 A neutron travels at high speed towards a uranium-235 nucleus. The Fission Process
  • Slide 6
  • U 235 92 n 1 0 A neutron travels at high speed towards a uranium-235 nucleus. The Fission Process
  • Slide 7
  • U 235 92 n 1 0 The neutron strikes the nucleus which then captures the neutron. The Fission Process
  • Slide 8
  • U 236 92 The nucleus changes from being uranium-235 to uranium-236 as it has captured a neutron. The Fission Process
  • Slide 9
  • The uranium-236 nucleus formed is very unstable. It transforms into an elongated shape for a short time. The Fission Process
  • Slide 10
  • The uranium-236 nucleus formed is very unstable. It transforms into an elongated shape for a short time. The Fission Process
  • Slide 11
  • The uranium-236 nucleus formed is very unstable. It transforms into an elongated shape for a short time. The Fission Process
  • Slide 12
  • It then splits into 2 fission fragments and releases neutrons. 141 56 Ba 92 36 Kr n 1 0 n 1 0 n 1 0 The Fission Process
  • Slide 13
  • It then splits into 2 fission fragments and releases neutrons. 141 56 Ba 92 36 Kr n 1 0 n 1 0 n 1 0 The Fission Process
  • Slide 14
  • It then splits into 2 fission fragments and releases neutrons. 141 56 Ba 92 36 Kr n 1 0 n 1 0 n 1 0 The Fission Process
  • Slide 15
  • It then splits into 2 fission fragments and releases neutrons. 141 56 Ba 92 36 Kr n 1 0 n 1 0 n 1 0 The Fission Process Energy
  • Slide 16
  • Nuclear Fission Examples U 235 92 + Ba 141 56 + n 1 0 3 n 1 0 + Kr 92 36 U 235 92 + Cs 138 55 + n 1 0 2 n 1 0 + Rb 96 37
  • Slide 17
  • Review: Balancing Nuclear Equations Mass numbers and Atomic numbers must add up on both sides of the reaction arrow. 100 Fm 54 Xe + ____ + 4 0 n 256 1401 For Atomic numbers 100 = 54 + X X = 46 For Mass Numbers: 256 = 140 + X + 4 X = 112 46 Pd 112
  • Slide 18
  • 18 White Boards Supply the missing atomic symbol to complete the equation for the following nuclear fission reaction. 1 n + 235 U 137 Te + ? X + 2 1 n + energy 0 92 52 ? 0
  • Slide 19
  • 19 Solution 1 n + 235 U 137 Te + 97 Zr + 2 1 n + energy 0 92 52 40 0
  • Slide 20
  • Fission Chain Reactions One fission reaction can lead to more fission reactions in a process called a chain reaction. Example - The fission of Uranium-235
  • Slide 21
  • Chain Reaction of Uranium-235
  • Slide 22
  • A chain reaction can only occur if the starting material has enough mass to sustain a chain reaction. This amount is called the critical mass. Nuclear Fission is what occurs in Nuclear Reactors and Atomic Bombs. The Nuclear reactor is a controlled fission reaction, the bomb is not. The chain reaction releases a large amount heat and energy that produces an atomic explosion.
  • Slide 23
  • Slide 24
  • Nuclear Fusion The combining of atomic nuclei to form a larger atom is called fusion Nuclear fusion occurs in the sun when two nuclei with low mass numbers combine to produce a single nucleus with a higher mass number. Fusion releases large amounts of energy. Example: 4 H + 2 0 e He + energy 1 1 2 4 Energy
  • Slide 25
  • Nuclear Fusion
  • Slide 26
  • The Fusion Process H 2 1 H 3 1
  • Slide 27
  • H 2 1 H 3 1
  • Slide 28
  • H 2 1 H 3 1
  • Slide 29
  • H 2 1 H 3 1
  • Slide 30
  • Slide 31
  • Slide 32
  • Slide 33
  • Slide 34
  • He 4 2 n 1 0 ENERGY
  • Slide 35
  • The Fusion Process He 4 2 n 1 0 ENERGY
  • Slide 36
  • The Fusion Process He 4 2 n 1 0 ENERGY
  • Slide 37
  • The Fusion Process He 4 2 n 1 0 ENERGY
  • Slide 38
  • Nuclear fusion is what powers our sun - and all stars.
  • Slide 39
  • And also - Hydrogen Bombs
  • Slide 40
  • Fusion Fusion reactions also release very large amount of energy but require extremely high temperatures to start. Nuclear fusion also occurs in new stars and is how all of our elements were made. He + He Be + energy 4 2 2 48 4 He + Be C + energy 4 2 8 4 12 6
  • Slide 41
  • Other Fusion Reactions Hydrogen Bomb or possible Fusion nuclear reactor reaction 3 H + 2 H 4 He + 1 n New elements discovered: 20 Ca + 95 Am 115 Uup 115 Uup 113 Uut + 2 He 11 2 0 4
  • Slide 42
  • Remember: Nuclear fission and fusion both occur with an incredible release of energy. Energy
  • Slide 43
  • Indicate if each of the following describes 1) nuclear fissionor 2) nuclear fusion. ___ A. a nucleus splits. ___ B. large amounts of energy are released ___ C. small nuclei form larger nuclei. ___ D. hydrogen nuclei react. ___ E. several neutrons are released. Learning Check
  • Slide 44
  • 44 Indicate if each of the following is 1) nuclear fissionor 2) nuclear fusion. 1 A. a nucleus splits. 1, 2 B. large amounts of energy are released. 2 C. small nuclei form larger nuclei. 2 D. hydrogen nuclei react. 1 E. several neutrons are released. Solution
  • Slide 45
  • Chemical Reactions Involve changes in electrons Acids & Bases, combustion, displacement The same atoms appear on both sides of the reaction. Small amount of energy generated Burning fossil fuels Nuclear Reactions Involve changes in the nucleus Nuclear fusion, nuclear fission New atoms appear as products of the reaction. Large amount of energy generated 1 million times more than chemical reactions Nuclear fusion on the sun Nuclear fission for reactors
  • Slide 46
  • Decay vs. Nuclear Reactions Alpha, beta, and gamma decay occur as ONE atom tries to increase its stability by getting rid of a few neutrons, or protons & neutrons. The product is an alpha, beta, or gamma particle and ONE new atom. There is only ONE thing on the left hand side. Nuclear reactions involve more than just getting rid of a few protons or neutrons. The new atoms produced are VERY different elements than the reactant. Nuclear reactions must be started, so there are 2 things on the left hand side. Nuclear fission: makes 2 or more much smaller atoms Nuclear fusion: makes 1 much larger atom
  • Slide 47
  • Nuclear Fission What are the differences between the 2 above nuclear equations?? Alpha Decay

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