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Nuclear Chemistry Fusion and Fission

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Page 1: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Nuclear ChemistryFusion and Fission

Page 2: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

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.

Page 3: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Nuclear Fission

Page 4: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

U23592n

1 0

The Fission Process

A neutron travels at high speed towards a uranium-235 nucleus.

Page 5: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

U23592n

1 0

A neutron travels at high speed towards a uranium-235 nucleus.

The Fission Process

Page 6: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

U23592n

1 0

A neutron travels at high speed towards a uranium-235 nucleus.

The Fission Process

Page 7: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

U23592n

1 0

The neutron strikes the nucleus which then captures the neutron.

The Fission Process

Page 8: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

U23692

The nucleus changes from being uranium-235 to uranium-236 as it has captured a neutron.

The Fission Process

Page 9: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The uranium-236 nucleus formed is very unstable.

It transforms into an elongated shape for a short time.

The Fission Process

Page 10: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The uranium-236 nucleus formed is very unstable.

It transforms into an elongated shape for a short time.

The Fission Process

Page 11: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The uranium-236 nucleus formed is very unstable.

It transforms into an elongated shape for a short time.

The Fission Process

Page 12: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

It then splits into 2 fission fragments and releases neutrons.

14156Ba

9236Kr

n 1 0

n 1 0

n 1 0

The Fission Process

Page 13: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

It then splits into 2 fission fragments and releases neutrons.

14156Ba

9236Kr

n 1 0

n 1 0

n 1 0

The Fission Process

Page 14: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

It then splits into 2 fission fragments and releases neutrons.

14156Ba

9236Kr

n 1 0

n 1 0

n 1 0

The Fission Process

Page 15: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

It then splits into 2 fission fragments and releases neutrons.

14156Ba

9236Kr

n 1 0

n 1 0

n 1 0

The Fission Process

Energy

Page 16: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Nuclear Fission Examples

U235

92 +Ba141

56+ n1

03n

1

0 +Kr 92

36

U235

92 +Cs138

55+ n1

02n

1

0 +Rb 96

37

Page 17: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Review: Balancing Nuclear Equations

• Mass numbers and Atomic numbers must add up on both sides of the reaction arrow.

•100Fm 54Xe + ____ + 4 0n256 140 1

For Atomic numbers 100 = 54 + X X = 46

For Mass Numbers: 256 = 140 + X + 4 X = 112

46Pd112

Page 18: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

18

White 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

Page 19: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

19

Solution

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

Page 20: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

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

Page 21: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Chain Reaction of Uranium-235

Page 23: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)
Page 24: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

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 + energy1

1

-1 2

4 Energy

Page 25: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Nuclear Fusion

Page 26: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

H 2 1

H 3 1

Page 27: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

H 2 1

H 3 1

Page 28: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

H 2 1

H 3 1

Page 29: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

H 2 1

H 3 1

Page 30: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

Page 31: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

Page 32: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

Page 33: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

Page 34: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

He 4 2

n 1 0

ENERGY

Page 35: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

He 4 2

n 1 0

ENERGY

Page 36: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

He 4 2

n 1 0

ENERGY

Page 37: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

The Fusion Process

He 4 2

n 1 0

ENERGY

Page 38: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Nuclear fusion is what powers our sun - and all stars.

Page 39: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

And also - Hydrogen Bombs

Page 40: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

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 + energy42 2

4 84

He + Be C + energy42

84

126

Page 41: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Other Fusion Reactions

• Hydrogen Bomb or possible Fusion nuclear reactor reaction

• 3H + 2H 4He + 1n

• New elements discovered:• 20Ca + 95Am 115Uup

•115Uup 113Uut + 2He

1 1 2 0

4

Page 42: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Remember:Nuclear fission and fusion

both occur with an incredible release of energy.

Energy

Page 43: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Indicate if each of the following describes

1) nuclear fission or 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

Page 44: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

44

Indicate if each of the following is

1) nuclear fission or 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

Page 45: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

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

Page 46: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Decay vs. Nuclear Reactions• Alpha, beta, and gamma

decay occur as ONE atom tries to increase it’s 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

Page 47: Nuclear Chemistry Fusion and Fission. Nuclear Fission The splitting of a nucleus into smaller fragments is called nuclear fission. Heavy atoms (mass number>60)

Nuclear Fission

What are the differences between the 2 above nuclear equations??

Alpha Decay