Tro Chapter 19:
Radioactivity and Nuclear Chemistry : An
Overview of nuclear transformations
• Medical diagnostics
• Cancer treatment
• Generation of electricity
• Propulsion
On-line HW – due
• Sub-atomic particle research Tuesday, 12/7/10 at
11:59 PM; quiz 5
• Weapons/warheads
WEDNESDAY
12/8/10
Radioactivity and Nuclear Energy
440 power plants in 30 countries
Global production tripled from 1980 - 2000
% used for electricity
are shown in
parentheses
Radioactivity in Medicine and other applications
1 rad = 0.01 J/kg body tissue; dose in rads x biological effectiveness factor = does in rems
Tro
19.3
Common Particles in Radioactive and
Nuclear Transformations
Some Nuclear Equations
Mass number
N=A-Z
Atomic number
Number of neutrons
Thorium formation
Protactinium formation
N = # neutrons; A = mass #; Z = # protons
Tro 19.6
14C
formation
14C
decay
A skull believed to belong to an ancient human being is
found to have a carbon-14-decay rate of 4.50
disintegrations per minute per gram of carbon (dis. g-1 C).
If living organisms have a decay rate of 15.3 dis. g-1 C,
how old is the skull?
k = 1.209 x 10-4 yr-1
t = 10,122 years!
Converting Mass to Energy: Mass Defect and Nuclear Binding Energy
Tro 19.8
Nuclear Power – Using Fission to generate electricity
Tro 19.7
E = mc2
What is the mass defect and nuclear energy per nucleon for U-238, which has a
mass of 238.050784?
92(1.00783) amu + 146(1.00866) amu – 238.050784 amu
Mass defect = 1.933936 amu (1.66054 x 10-27 kg per amu)
Neutron sources
include 9Be and 2H
following gamma
radiation
Nuclear binding energy
Binding energy per nucleon – 1801.46/238 = 7.569 MeV/nucleon
1 MeV (megaelectron volt) = 1.602 x 10-13 J
For U-235 - 82 terajoules per kG or 20,000 tons of TNT
Nuclear Fuel Cycle
Major Suppliers:
Canada, Australia,
Russia, Niger, Ukraine
and Kazakstan
Control rods: Ag-In-Cd; B-Fe; Hf
Tro 19.9
Nuclear Fusion: The power of the sun