nuclear chemistry fusion and fission

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Nuclear Chemistry Fusion and Fission. 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 . - PowerPoint PPT Presentation

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Unit 2 The Atom

Nuclear ChemistryFusion and FissionNuclear FissionThe 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.Nuclear Fission

U23592n 1 0The Fission ProcessA neutron travels at high speed towards a uranium-235 nucleus.U23592n 1 0A neutron travels at high speed towards a uranium-235 nucleus.The Fission ProcessU23592n 1 0A neutron travels at high speed towards a uranium-235 nucleus.The Fission ProcessU23592n 1 0The neutron strikes the nucleus which then captures the neutron.The Fission ProcessU23692The nucleus changes from being uranium-235 to uranium-236 as it has captured a neutron.The Fission ProcessThe uranium-236 nucleus formed is very unstable.It transforms into an elongated shape for a short time.The Fission ProcessThe uranium-236 nucleus formed is very unstable.It transforms into an elongated shape for a short time.The Fission ProcessThe uranium-236 nucleus formed is very unstable.It transforms into an elongated shape for a short time.The Fission ProcessIt then splits into 2 fission fragments and releases neutrons.14156Ba 9236Krn 1 0n 1 0n 1 0The Fission ProcessIt then splits into 2 fission fragments and releases neutrons.14156Ba 9236Krn 1 0n 1 0n 1 0The Fission ProcessIt then splits into 2 fission fragments and releases neutrons.14156Ba 9236Krn 1 0n 1 0n 1 0The Fission ProcessIt then splits into 2 fission fragments and releases neutrons.14156Ba 9236Krn 1 0n 1 0n 1 0The Fission ProcessEnergyNuclear Fission ExamplesU23592+Ba14156+n103n10+Kr 9236U23592+Cs13855+n102n10+Rb 9637Review: Balancing Nuclear EquationsMass numbers and Atomic numbers must add up on both sides of the reaction arrow.

100Fm 54Xe + ____ + 4 0n2561401For Atomic numbers 100 = 54 + X X = 46For Mass Numbers: 256 = 140 + X + 4 X = 11246Pd112= 1718White Boards Supply the missing atomic symbol to complete the equation for the following nuclear fission reaction.

1n + 235U 137Te + ?X + 2 1n + energy0 92 52 ? 0

19Solution1n + 235U 137Te + 97Zr + 2 1n + energy0 92 52 40 0

Fission Chain ReactionsOne fission reaction can lead to more fission reactions in a process called a chain reaction.Example - The fission of Uranium-235

Chain Reaction of Uranium-235A 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.

Nuclear FusionThe combining of atomic nuclei to form a larger atom is called fusionNuclear 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 + energy11-124

EnergyNuclear Fusion

The Fusion ProcessH 2 1H 3 1The Fusion ProcessH 2 1H 3 1The Fusion ProcessH 2 1H 3 1The Fusion ProcessH 2 1H 3 1The Fusion ProcessThe Fusion ProcessThe Fusion ProcessThe Fusion ProcessThe Fusion ProcessHe 4 2n 1 0ENERGYThe Fusion ProcessHe 4 2n 1 0ENERGYThe Fusion ProcessHe 4 2n 1 0ENERGYThe Fusion ProcessHe 4 2n 1 0ENERGYNuclear fusion is what powers our sun - and all stars.

And also - Hydrogen Bombs

FusionFusion 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 + energy422484 He + Be C + energy4284126Other Fusion ReactionsHydrogen Bomb or possible Fusion nuclear reactor reaction 3H + 2H 4He + 1n

New elements discovered: 20Ca + 95Am 115Uup

115Uup 113Uut + 2He11204Remember:Nuclear fission and fusion both occur with an incredible release of energy. EnergyIndicate if each of the following describes1) 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 Check44Indicate if each of the following is1) 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.

SolutionChemical ReactionsInvolve changes in electronsAcids & Bases, combustion, displacement

The same atoms appear on both sides of the reaction.

Small amount of energy generatedBurning fossil fuels

Nuclear ReactionsInvolve changes in the nucleusNuclear fusion, nuclear fission

New atoms appear as products of the reaction.

Large amount of energy generated 1 million times more than chemical reactionsNuclear fusion on the sunNuclear fission for reactorsDecay vs. Nuclear ReactionsAlpha, 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 atomsNuclear fusion: makes 1 much larger atom

Nuclear FissionWhat are the differences between the 2 above nuclear equations??

Alpha Decay47

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