Nuclear Chemistry Notes Power Point.ppt

3
A little history…
• One of the pieces of evidence for the
fact that atoms are made of smaller
particles came from the work of
Madame Curie (1876-1934).
• She discovered radioactivity,
the spontaneous disintegration of
some elements into smaller pieces.
T

4
Isotopes – Remember?
• Not all atoms of the same element have
the same mass due to different numbers
of neutrons in those atoms.
• There are three naturally occurring
isotopes of uranium:
– Uranium-234
– Uranium-235
– Uranium-238

6
Nuclear Reactions Involve the nucleus…
• Remember that the nucleus is comprised of the
two nucleons, protons and neutrons.
• The number of protons is the atomic number.
• The number of protons and neutrons together
is effectively the mass of the atom.

I. The Nucleus
A. The atomic nucleus is made up of protons and neutrons which are
collectively called nucleons.
– Nuclide – in nuclear chemistry the atom is referred to as the nuclide.
– Nuclides are represented by two ways:
Radium-228 OR 228 (mass number)
(name of element followed Ra (symbol)
by mass number) 88 (atomic number)
Mass Number is the # of protons + # of neutrons
Atomic Number is the # of protons as well as the # of
electrons

8
So…
• Do nuclear reactions produce physical or
chemical changes?
– Is a NEW SUBSTANCE produced during a
nuclear reaction?
– Is the reactant the same substance as the
product?
U
238
92  Th
234
90
He
4
2
+

9
Yes, but…
• You were taught that chemical changes
result in a “new” substance, so it would
seem these changes are chemical.
– Classically, “chemical changes” involve
changes in the electron cloud.
– That is not what is happening here, this
change involves the NUCLEUS.
– These are neither chemical nor physical
reactions – they are NUCLEAR reactions.

10
Furthermore…
• Nuclear reactions don’t strictly obey the
Law of Conservation of Mass the way
“normal” chemical reactions do.
– To be clear though, the mass is not necessarily
conserved in these reactions – BUT THE
PARTICLES ARE.
• Some of the mass gets converted into
energy, as described in a very famous
equation…

11
You may have seen this
equation… it describes
Mass Defect
• What this means is that mass is just a form of energy.
• The difference between mass as energy and other forms
of energy is that mass has gravity and inertia.
E=mc2
Energy
Mass
Speed of light
constant

12
Huh? How do we know that?
• In stars, hydrogen is
converted into
helium.
• 100% of the original
mass is not
accounted for after
this process – only
99.7%.
• The rest is given off
as energy in the form
of gamma radiation
and neutrinos.

13
Wait, you said NEUTRINO?
• A particle with very low mass, around that of an
electron, and no electrical charge, the neutrino is
an elusive subatomic particle.
• Neutrinos travel at almost the speed of light, and
many quadrillions of them penetrate your body
every second.
• But because neutrinos have such low mass, no
charge, and interact only slightly with atoms, they
can penetrate several light years of densely packed
matter before interacting with an atom. For this
reason they are very difficult to detect.

II. Mass Defect and Nuclear Stability
A. Let’s look at helium-4:
2 protons (2 X 1.007276amu) = 2.014552amu
2 neutrons (2 X 1.008665amu) = 2.017330amu
2 electrons (2 X 0.0005486amu) =0.001097amu
total combined mass: 4.032979amu
The actual mass of the atom is measured to be
4.00260amu! That is 0.03038amu less then the sum
of all of its particles, it is also called the mass
defect.

B. The mass defect is caused by the conversion of
mass (m) to energy (E) when the nucleus was
originally formed.
C. Using Einstein’s equation E=mc2, we can actually
calculate the energy that was formed when the
nucleus was formed! This is called the nuclear
binding energy. (It can also be thought of as the
amount of energy required to break apart the
nucleus; therefore, the nuclear binding energy is
also a measure of the stability of a nucleus.)

How much energy was released when a single helium-4 atom was
formed? (In other words, calculate the nuclear binding energy of one
helium-4 atom. The measured atomic mass of helium-4 is 4.00260amu.)
Step 1: Find the mass defect.
4.032979amu – 4.00260amu = 0.03038amu
Step 2: Using the conversion 1amu =1.6605 X 10-27 kg
convert the mass from amu’s to kilograms.
?kg  0.03038amu X 1.6605 X 10-27 kg = 5.0446 X 10-29
kg
1amu
Step 3: Calculate the energy using E = mc2.
c is a constant and it equals 3.00 X 108 m/sec
E = (5.0446 X 10-29 kg) (3.00 X 108 m/sec)2
E = 4.54 X 10-12 kg  m2 or J (J = kg  m2)

Practice: Calculate the nuclear binding
energy of a sulfur-32 atom. The
measured atomic mass of sulfur-32 is
32.080amu.

III. Nuclear Reactions – Chemical reactions involve the breaking and
forming of bonds between different atoms. In a nuclear reaction the
situation is different – in a nuclear reaction changes occur involving the
number of protons, neutrons, or electrons in a single atom.
Proton is symbolized: 1
p
1
Electron is symbolized: 0 0
e OR 
-1 -1
Neutron is symbolized: 1
n
0

In nuclear equations the total of the atomic number and the
total of the mass number must be equal on both sides of the
equation. Example:
9 4 12 1
Be + He  C + n
4 2 6 0
Mass Number: 9+4 = 13 12+1 = 13
Atomic Number: 4+2 = 6 6+0 = 6
This is also called a transmutation reaction,
because the beryllium-9 became carbon-12.

Example:
212 4 208
Po  He + Pb
84 2 82
Mass Number:
212 4+208 = 212
Atomic Number:
84 2+82 = 84

Practice: Complete the following
nuclear equations:
1.
218 4
Po  He +
84 2

2.
253 4 1
Es + He  + n
99 2 0

IV. Radioactive Decay is the spontaneous disintegration of a
nucleus into a slightly lighter nucleus, accompanied by
emission of particles, electromagnetic radiation, or both.
Types of Radioactive Decay

IV. Radioactive Decay is the spontaneous disintegration of a
nucleus into a slightly lighter nucleus, accompanied by
emission of particles, electromagnetic radiation, or both.
A. Alpha Emission – an alpha particle () is 2
protons and 2 neutrons (or a helium atom) bound
together and is emitted from the nucleus during
some kinds of radioactive decay.
210 206 4
Po  Pb + He
84 82 2
Clothes will shield you form alpha particles.

B. Beta Emission – a beta particle () is an electron
emitted from the nucleus when a neutron is converted
to a proton.
1 1 0
n  p + 
0 1 -1
14 14 0
C  N + 
6 7 -1
Metal foil will shield you from beta particles.

C. Positron Emission – a positron is a particle that is emitted
from the nucleus when a proton is converted into a neutron.
1 1 0
p  n + 
1 0 1
38 38 0
K  Ar + 
19 18 1

D. Gamma Emission – gamma rays () are
high-energy electromagnetic waves emitted
from a nucleus as it changes from an excited
state to a ground energy state. Very similar to
light, but is much more dangerous. Gamma
emission usually occurs immediately
following other types of decay. (Page 713 )
Lead or concrete will protect you from gamma
rays.

Practice: Complete the following
nuclear reactions:
1.
239 242 1
Pu +  Cm + n
94 96 0

4. Write an equation to represent
the decay of thorium-230 by alpha
emission.

40
Radioactivity
• It is not uncommon for some nuclides of
an element to be unstable, or radioactive.
• We refer to these as radionuclides.
• There are several ways radionuclides can
decay into a different nuclide.

41
Alpha Decay
Loss of an -particle (a helium nucleus)
He
4
2
U
238
92
 Th
234
90
He
4
2
+
T

42
Beta Decay
(a.k.a Beta Minus Decay)
Loss of a -particle (a high energy electron)
an excess neutron becomes a proton, and the nucleus
emits an electron and an antineutrino. The electron is
the beta particle, while the antineutrino is a particle
with some unusual properties.

0
−1 e
0
−1
or
I
131
53
Xe
131
54
 + e
0
−1
T

43
Positron Emission
(a.k.a Beta Plus Decay)
Loss of a positron (a particle that has the
same mass as but opposite charge than an
electron)
a proton is converted into a neutron, with the nucleus
emitting a positron and a neutrino. Beta particles can be
electrons or positrons depending on whether a nucleus goes
through beta minus or beta plus decay.
e
0
1
C
11
6
 B
11
5
+ e
0
1

44
About this Beta particle…
• The cause of beta emission is an excess of
neutrons in the nucleus.
• When there are way more neutrons than
protons in a nucleus, a neutrons can split – or
degenerate - into a proton and an electron This
electron is then ejected from the nucleus at high
speed.
– …beta particles are not themselves radioactive, they
cause damage ballistically, breaking chemical bonds
and creating ions which do damage to tissue.
• This increases the atomic number of the atom
by 1 and also increases the atom’s stability.

45
Gamma Emission
Loss of a -ray (high-energy radiation that
almost always accompanies the loss of a
nuclear particle)

0
0
T

46
Electron Capture (K-Capture)
• During this process, one of the protons in the atom's
nucleus pulls in an orbiting electron and neutralizes
both the electron and itself.
• This causes the atom to decay and become a
different element with the same atomic mass.
p
1
1
+ e
0
−1  n
1
0
This causes the atom to decay and become a
different element (one less proton) with the same
atomic mass.

47
Short Notation:
e
0
1

He
4
2
• Alpha (ά) – a positively
charged helium isotope - we
usually ignore the charge because it involves
electrons, not protons and neutrons
•Beta (β) – an electron
•Gamma (γ) – pure energy;
called a ray rather than a
particle

0
0
T

48
Notation of Other Nuclear
Particles…
e
0
1

n
1
0
• Neutron
• Positron – a positive
electron
•Proton – usually referred to
as hydrogen-1
•Any other elemental isotope
H
1
1
T

50
Nuclear Reactions
• Alpha emission
Note that mass number (A) goes down by 4
and atomic number (Z) goes down by 2.
Nucleons (nuclear particles… protons and
neutrons) are rearranged but conserved

51
Nuclear Reactions
• Beta emission
Note that mass number (A) is unchanged
and atomic number (Z) goes up by 1.

52
Other Types of Nuclear Reactions
Positron (0
+1): a positive electron
Electron capture: the capture of an electron
207 207

E. Effects of Radiation: The effects of
radiation depends on the amount and
exposure. Massive doses can be deadly.
DNA molecules are sensitive to alpha,
beta, positron, gamma, and x-rays.

Estimate Your Personal
Annual Radiation Dose
http://www.ans.org/pi/resources/dosechart/
We live in a radioactive world – humans always have.
Radiation is part of our natural environment. We are
exposed to radiation from materials in the earth itself,
from naturally occurring radon in the air, from outer
space, and from inside our own bodies (as a result of
the food and water we consume). This radiation is
measured in units called millirems (mrems). The
average dose per person from all sources is about 360
mrems in a given year (largely due to medical
procedures we may undergo). International Standards
allow exposure to as much as 5,000 mrems a year for
those who work with and around radioactive material.

Estimate Your Personal Annual
Radiation Dose American Nuclear Society
Factors Common Sources of Radiation
Where
You
Live
Cosmic radiation (from outer space)
Exposure depends on your elevation (how much air
is above you to block
radiation).
Amounts are listed in mrem (per year).
At sea level 26 mrem
2 – 3000 ft 35 mrem 6 – 7000 ft 66 mrem
0 – 1000 ft 28 3 – 4000 ft 41 7 – 8000 ft 79
1 – 2000 ft 31 4 – 5000 ft 47 8 – 9000 ft 96
5 – 6000 ft 52
[Elevation of cities (in feet): Atlanta 1050; Chicago 595; Dallas 435; Denver 5280; Las
Vegas 2000; Minneapolis 815; Pittsburgh 1200; St. Louis 455; Salt Lake City 4400;
Spokane 1890.]
Your Annual Dose Total: 26 mrems

Where
You
Live
Terrestrial (from the ground)
•If you live in a state that borders the
Gulf or Atlantic Coasts, add 16 mrem.
•If you live in the Colorado Plateau
area (around Denver), add 63 mrem.
•If you live anywhere else in the
continental U.S., add 30 mrem.
Your Annual Dose Total: 26 + 16 mrems

Where
You
Live
House Construction
If you live in a stone, adobe, brick, or concrete
building, add 7 mrem.
Power Plants
•If you live within 50 miles of a nuclear power
plant, add 0.01 mrem.
•If you live within 50 miles of a coal-fired power
plant, add 0.03 mrem.
Your Annual Dose Total: _________mrems

Food
Water
Air
Internal Radiation***
From food (Carbon-14 and Potassium-40)
& from water (radon dissolved in water),
add 40 mrem.
From air (radon), add 200 mrem.

How
You
Live
Weapons test fallout (less than 1*), add 1 mrem
Jet Plane Travel, add 0.5 mrem/hour in air
If you have porcelain crowns or false teeth**,add
0.07 mrem
If you wear a luminous wristwatch, add 0.06
mrem
If you go through luggage inspection at airport,
add 0.02 mrem/pass

How
You
Live
If you watch TV*, add 1 mrem
If you use/view a computer screen*, add
1 mrem
If you have a smoke detector, add 0.08 mrem
If you use a gas camping lantern, add 0.2 mrem
If you wear a plutonium-powered pacemaker,
add 100 mrem

Medical
Tests
Medical Diagnostic Test – Number of millirems
per procedure
X-Rays:
Extremity (arm, hand, foot, or leg), add 1 mrem
Dental, add 1 mrem
Chest, add 6 mrem
Pelvis/hip, add 65 mrem
Skull/neck, add 20 mrem

Medical
Tests
Medical Diagnostic Test – Number of millirems
per procedure
X-Rays (continued) :
Barium enema, 405 mrem
Upper GI, add 245 mrem
CAT Scan (head and body), add 110 mrem
Nuclear Medicine (e.g., thyroid scan), add 14
mrem

Radiation Dose Test Info
* The value is less than 1, but adding a value of 1 would be
reasonable.
**Some of the radiation sources listed in this chart result in an
exposure to only part of the body. For example, false teeth or
crowns result in a radiation dose to the mouth. The annual dose
numbers given here represent the "effective dose" to the
whole body.
***Average values.
Primary sources for this information are National Council on Radiation and Measurements Reports: #92 Public
Radiation Exposure from Nuclear Power Generation in the United States (1987); #93 Ionizing Radiation Exposure
of the Population of the United States (1987); #94 Exposure of the Population in the United States and
Canada from Natural Background Radiation (1987); #95 Radiation Exposure of the U.S. population from Consumer
Products and Miscellaneous Sources, (1987); and #100 Exposure of the U.S. Population from Diagnostic Medical
Radiation (1989).
Copyright 2000 American Nuclear Society
http://www.ohio.edu/ehs/docs/10_persnl_rad_dose.pdf

Health Effects of a Single Dose of
Radiation Exposure
http://www.epa.gov/radiation/understand/health_effects.html
Exposure (rem) and Health Effect
5-10 Changes in blood chemistry
50 Nausea
55 Fatigue
70 Vomiting
75 Hair loss
90 Diarrhea
100 Hemorrhage

Health Effects of a Single Dose of
Radiation Exposure
http://www.epa.gov/radiation/understand/health_effects.html
Exposure (rem) and Health Effect
400 Possible death (within 2 months)
1,000 Destruction of intestinal lining, internal bleeding, and
death (within 1-2 weeks)
2,000 Damage to central nervous system, loss of
consciousness; (within minutes)
Death (hours to days)

V. Half-life – is the time required for half the atoms of a
radioactive nuclide to decay. Each radioactive nuclide has its
own half-life. Example: Carbon-14 has a half-life of 5715-
5730 years. Page 708
Example Problem: Phosphorus-32 has a half-life of
14.3 days. How many mg of phosphorus-32 remain
after 57.2 days if you start with 4mg of the isotope?
Amount of Phosphorus-32 Time Elapsed
4mg 0 days have past
2mg 14.3 days have passed
1mg 28.6 days have passed
0.5mg 42.9 days have passed
0.25mg 57.2 days have passed

Another way to work half-life problems:
# of half-lives = time elapsed X ratio for half-life
# of half-lives = 57.2 days X 1 half-life = 4 half-lives
14.3 days
So now we know the answer will be:
4mg X ½ X ½ X ½ X ½ = 0.25mg

Write this down:
Original Mass(½)x = Final Mass
x = Number of Half Lives
x= Time Elapsed
One Half Life

Practice:
1. The half-life of polonium-210 is 138.4 days. How
many mg of polonium-210 remain after 415.2 days
if you start with 2mg of the isotope?
# of half-lives = 415.2 days X 1 half-life = 3 half-lives
138.4 days
2mg X ½ X ½ X ½ = 0.25mg

2. The half-life of radon-222 is 3.824 days. After
what time will ¼ of a given amount of radon-222
remain?
To obtain ¼ of any amount, it will have to go through
2 half-lives:
½ X ½ = ¼
Therefore to get ¼ of any amount of radon-222 it will
take 7.648 days (enough time for 2 half-lives).

74
Half-Life
•HALF-LIFE is the time that it takes for 1/2
a sample to decompose.
• The rate of a nuclear transformation
depends only on the “reactant”
concentration.

75
Half-Life
Decay of 20.0 mg of 15O. What remains after 3 half-lives?
After 5 half-lives?

76
Kinetics of Radioactive Decay
For each duration (half-life), one half of the
substance decomposes.
For example: Ra-234 has a half-life of 3.6 days
If you start with 50 grams of Ra-234
After 3.6 days > 25 grams
After 7.2 days > 12.5 grams
After 10.8 days > 6.25 grams

VI. Nuclear Radiation
A. Radiation Exposure - Measured in rem’s (it is a
quantity of radiation that causes change to human
tissue).
B. Detecting Radiation (page 714): Film badges,
Geigir-Muller counters, and scintillation are
three common devices used to detect and measure
nuclear radiation. International standards allow up
to 5rem’s a year exposure for those who work with
and around radioactive material.

Film Badges:
Film badges are worn the entire time a
person is at work. At specific times the
film is removed and developed. The
strength and type or radiation exposure
are determined from the darkening of the
film.

Geiger Müller Counters:
A Geiger Müller counter is a gas
filled metal tube used to detect
radiation.

80
Measuring Radioactivity
• A Geiger counter is used to measure the amount of
activity present in a radioactive sample.
– Ionizing radiation creates ions, which conduct a current that
is detected by the instrument. It “clicks” faster when close to
radiation.

Scintillation Counters:
This is a device that uses a
phosphorus coated surface to
detect radiation.

C. Applications of Nuclear Radiation
1. Radioactive Dating
2. Radioactive Tracers – Medical uses
3. Radioactive Tracers – Agricultural uses
4. Radiation Therapy

84
Radiocarbon Dating
Radioactive C-14 is formed in the upper atmosphere
by nuclear reactions initiated by neutrons in
cosmic radiation
14N + 1
on ---> 14C + 1H
The C-14 is oxidized to CO2, which circulates
through the biosphere.
When a plant dies, the C-14 is not replenished.
But the C-14 continues to decay with t1/2 = 5730
years.
Activity of a sample can be used to date the sample.

Radioactive Tracers:
These are incorporated into substances so that
movement of the substance can be followed
by radiation detectors. (Page 715)
Detection of radioactive tracers can be used to
diagnose cancer and other diseases.

86
Nuclear Medicine: Imaging
Thyroid imaging using Tc-99m

Radioactive Tracers – Agricultural Uses:
In agriculture they are used to test the effect
of fertilizers, pesticides, and herbicides.
During the procedure the tracer is first
introduced into a substance being tested to
make the substance radioactive. Next,
plants are treated with the radioactive
substance. The radioactivity of the plant is
measured to determine location of the
substance.

88
Food Irradiation
•Food can be irradiated with  rays from
60Co or 137Cs.
•Irradiated milk has a shelf life of 3 mo.
without refrigeration.
•USDA has approved irradiation of meats
and eggs.

Radiation Therapy:
This is commonly used to treat cancer. The
cancerous area can be treated with radiation
to kill the caner cells. (Some healthy cells
are killed as well, so the benefit and risks of
the treatment must be carefully considered
prior to treatment.) Gamma and beta
particles are most commonly used.

VII. Nuclear Fission and Fusion
A. Nuclear Fission – the splitting of a nucleus into
smaller fragments (the splitting is caused by
bombarding the nucleus with neutrons). This
process releases enormous amounts of energy.
(page 717)
A nuclear chain reaction is a reaction in which the
material that starts the reaction (neutron) is also one
of the products and can be used to start another
reaction.
1. Nuclear Reactors use controlled – fission
chain reactions to produce energy or radioactive
nuclides.

2. Nuclear Power Plants use heat from nuclear reactors to
produce electrical energy. They have 5 main components:
page 718
a. shielding – radiation absorbing material that is used to decrease
exposure to radiation.
b. fuel – uranium is most often used
c. control rods – neutron absorbing rods that help control the reaction
by limiting the number of free neutrons
d. moderator – water (sometimes carbon) is used to slow down the fast
neutrons produced by fission
e. coolant – water acts as a coolant and transports heat between the
reaction and the steam turbines to produce electric current
Nuclear Power Plants produce a great deal of energy, the
current problems with nuclear power plants include
environmental requirements, safety of operation, plant
construction costs, and storage and disposal of spent fuel
and radioactive waste.

3. Atomic Bomb – fission reaction

B. Nuclear Fusion – light mass nuclei combine to form a
heavier, more stable nucleus. Nuclear fusion releases even
more energy per gram of fuel then nuclear fission!!
1. Sun/Stars – four hydrogen nuclei combine at extremely
high temperatures and pressures to form a helium nucleus –
this is a fusion reaction.
2. Hydrogen Bomb (page 719)- uncontrolled fusion reactions
of hydrogen are the source of energy for the hydrogen
bomb. Hydrogen bombs generate a great deal more of
energy then an atomic bomb.
3. Fusion as a Source of Energy: because fusion reactions
generate a great deal more energy and their products are less
harmful then fission reactions. Research is being done to
try to use fusion instead of fission, there are a few problems:
temperature of 108 Kelvin is required and no known
material can withstand the temperature.

C. Nuclear Waste (produced from
fission and fusion reactions)
1. Types of Nuclear Waste
-spent fuel rods
-dismanteled nuclear
power plants
-military
-radioisotopes used
in many hospitals

2. Containment – on-site storage and off-site disposal
(Remember that every radioactive substance has a half-life,
some only a few months, others hundreds of thousands of
years.)
a. On-Site Storage – most common nuclear waste is spent
fuel rods from nuclear power plants
-water pools
-dry casks (concrete or steel)
b. Off-Site Disposal – disposal of nuclear waste is done with
the intention of never retrieving the materials.
-77 disposal sites around the United States
-new site near Las Vegas, Nevada
Yucca Mountain

104
Stability
of Nuclei
• Out of > 300 stable isotopes:
Even Odd
Odd
Even
Z
N
157 52
50 5
31
15P
19
9F 2
1H, 6
3Li, 10
5B, 14
7N, 180
73Ta

105
Band of
Stability and
Radioactive
Decay

106
Neutron-Proton Ratios
As nuclei get
larger, it takes a
greater number
of neutrons to
stabilize the
nucleus.

107
Stable Nuclei
The shaded
region in the
figure shows
what nuclides
would be
stable, the so-
called belt of
stability.

108
Stable Nuclei
• Nuclei above
this belt have too
many neutrons.
• They tend to
decay by emitting
beta particles.

109
Stable Nuclei
• Nuclei below the belt
have too many
protons.
• They tend to become
more stable by
positron emission or
electron capture.

110
Stable Nuclei
• There are no stable nuclei
with an atomic number
greater than 83.
–These nuclei tend to decay by
alpha emission, emitting alpha
particles.

111
Radioactive Series
• Large radioactive
nuclei cannot stabilize
by undergoing only one
nuclear transformation.
• They undergo a series
of decays until they
form a stable nuclide
(often a nuclide of
lead).

112
A Trend
Nuclei with an even
number of protons and
neutrons tend to be more
stable than nuclides that
have odd numbers of these
nucleons.

113
Representation of a fission process.

114
Nuclear Fission
• If there are not enough radioactive nuclides in
the path of the ejected neutrons, the chain
reaction will die out.
• Therefore, there must be a certain minimum
amount of fissionable material present for the
chain reaction to be sustained: Critical Mass.

115
Nuclear Fission & POWER
• Currently about 103
nuclear power plants in the
U.S. and about 435
worldwide.
• 17% of the world’s energy
comes from nuclear.
• Given recent events in
Japan, this will be
changing.

116
Nuclear Reactors
In nuclear reactors the heat generated by the
reaction is used to produce steam that turns a
turbine connected to a generator.

117
Nuclear Reactors
• The reaction is kept in
check by the use of control
rods.
• These block the paths of
some neutrons, keeping the
system from reaching a
dangerous supercritical
mass.
• Link (Hank explains how a
nuclear reactor works):
• http://www.youtube.com/w
atch?v=rBvUtY0PfB8

118
Nuclear Fusion
Fusion
Small nuclei “fuse” together.
They form a larger atomic nucleus.
2H + 3H 4He + 1n +
1 1 2 0
Energy

119
Here is a fusion reaction where Deutrium,
an isotope of hydrogen with 1 proton and 1
neutron, produces helium and a neutron
while releasing energy.

120
Where does fusion naturally
occur?
Fusion
• Since excessive
amounts of heat can
not be contained,
• To date, all attempts
at “cold” fusion have
FAILED.
• “Hot” fusion is
difficult to contain,
but happens in the
stars.

121
Nuclear Fusion
• Fusion would be a superior
method of generating power,
if we could make it happen,
and if we could control it here
on EARTH.
– The products of the reaction are
not radioactive, not dangerous!
– However, in order to achieve fusion, the material
must be in the plasma state at several million kelvins.

Nuclear Chemistry Notes Power Point.ppt

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Nuclear Chemistry Notes Power Point.ppt