Embed Size (px)
Citation preview
Nuclear Chemistry
Nuclear Chemistry
Types of RadiationTypes of RadiationNuclear DecayNuclear Decay
Half-LifeHalf-LifeApplicationsApplications
Big Bang MovieBig Bang Movie
Types of RadiationTypes of RadiationNuclear DecayNuclear Decay
Half-LifeHalf-LifeApplicationsApplications
Big Bang MovieBig Bang Movie
I
IV
III
II
He42
A. Types of RadiationA. Types of RadiationA. Types of RadiationA. Types of RadiationAlpha particle ()
helium nucleus Alpha Particle movie
paper2+
Beta particle (-) electron e0
-11-
leadPositron (+) positron e0
11+
Gamma () high-energy photon Radiation movie 0
concrete
B. Nuclear DecayB. Nuclear DecayB. Nuclear DecayB. Nuclear Decay
Alpha Emission
He Th U 42
23490
23892
parentnuclide
daughternuclide
alphaparticle
Numbers must balance!!
B. Nuclear DecayB. Nuclear DecayB. Nuclear DecayB. Nuclear Decay
Beta Emission
e Xe I 0-1
13154
13153
electronPositron Emission
e Ar K 01
3818
3819
positron
B. Nuclear DecayB. Nuclear DecayB. Nuclear DecayB. Nuclear Decay
Electron Capture
Pd e Ag 10646
0-1
10647
electronGamma Emission
Usually follows other types of decay.
Transmutation One element becomes another.
Band of StabilityBand of StabilityBand of StabilityBand of Stability
Atoms give off radiation in an attempt to increase stability.
Stability is determined by the ratio of protons to neutrons.
The neutron/proton ration needs to be between 1.0 and 1.5
B. Nuclear DecayB. Nuclear DecayB. Nuclear DecayB. Nuclear Decay
Why nuclides decay… need stable ratio of neutrons to protons
He Th U 42
23490
23892
e Xe I 0-1
13154
13153
e Ar K 01
3818
3819
Pd e Ag 10646
0-1
10647
DECAY SERIES TRANSPARENCY
Neutron to Proton RatioNeutron to Proton RatioNeutron to Proton RatioNeutron to Proton Ratio
Uranium-238 Decay Uranium-238 Decay SeriesSeries
Uranium-238 Decay Uranium-238 Decay SeriesSeries
C. Half-lifeC. Half-lifeC. Half-lifeC. Half-life
Half-life (t½) Time required for half the atoms of a
radioactive nuclide to decay. Shorter half-life = less stable.
C. Half-lifeC. Half-lifeC. Half-lifeC. Half-life
nif mm )( 2
1
mf: final massmi: initial massn: # of half-lives n = t/T1/2 t: total time elapsedT1/2: length of half life
C. Half-lifeC. Half-lifeC. Half-lifeC. Half-life Fluorine-21 has a half-life of 5.0 seconds. If you start
with 25 g of fluorine-21, how many grams would remain after 60.0 s?
GIVEN:
t½ = 5.0 s
mi = 25 g
mf = ?
total time = 60.0 s
n = 60.0s ÷ 5.0s =12
WORK:
mf = mi (½)n
mf = (25 g)(0.5)12
mf = 0.0061 g
Nuclear
Chemistry
Nuclear
Chemistry Fission & FusionFission & Fusion
Domino MovieDomino Movie
Fission & FusionFission & Fusion
Domino MovieDomino Movie
I
IV
III
II
A. FA. F issionissionA. FA. F issionission
splitting a nucleus into two or more smaller nuclei
1 g of 235U = 3 tons of coal
U23592
A. FA. F issionissionA. FA. F issionission
chain reaction - self-propagating reaction
Critical MassCritical MassCritical MassCritical Mass
critical mass - mass required to sustain a chain reaction Domino Unveiling Movie
B. FusionB. FusionB. FusionB. Fusioncombining of two nuclei to form one nucleus of larger mass thermonuclear reaction – requires temp of 40,000,000 K to sustain1 g of fusion fuel =
20 tons of coaloccurs naturally in
stars
HH 31
21
C. Fission vs. FusionC. Fission vs. FusionC. Fission vs. FusionC. Fission vs. Fusion
235U is limited danger of meltdown toxic waste thermal pollution
fuel is abundant no danger of meltdown no toxic waste not yet sustainable
FISSION
FUSION
Nuclear ChemistryNuclear ChemistryApplicationsApplicationsApplicationsApplications
I
IV
III
II
A. Nuclear PowerA. Nuclear PowerA. Nuclear PowerA. Nuclear Power
Fission Reactors- control rods are critical
Cooling Tower
A. Nuclear PowerA. Nuclear PowerA. Nuclear PowerA. Nuclear PowerFission Reactors movie
A. Nuclear PowerA. Nuclear PowerA. Nuclear PowerA. Nuclear Power
Fusion Reactors (not yet sustainable)
A. Nuclear PowerA. Nuclear PowerA. Nuclear PowerA. Nuclear Power
Fusion Reactors (not yet sustainable)
Tokamak Fusion Test Reactor
Princeton University
National Spherical Torus Experiment
A. Nuclear PowerA. Nuclear PowerA. Nuclear PowerA. Nuclear Power
Nuclear Power is relatively safe today; but when accidents occur, the damage can be devastating as Chernobyl demonstrated.
Boron control rods are used to regulated the chain reaction by absorbing neutrons.
B. Synthetic ElementsB. Synthetic ElementsB. Synthetic ElementsB. Synthetic Elements
Transuranium Elements elements with atomic #s above 92 synthetically produced in nuclear reactors and accelerators most decay very rapidly
Pu He U 24294
42
23892
B. Synthetic ElementsB. Synthetic ElementsB. Synthetic ElementsB. Synthetic Elements
The main Tevatron ring has a diameter of more than 0.8 km and a circumference of about 6.4 km. It uses conventional and superconducting magnets to accelerate particles to high speeds and energies.
C. Radioactive DatingC. Radioactive DatingC. Radioactive DatingC. Radioactive Dating
half-life measurements of radioactive elements are used to determine the age of an object movie
decay rate indicates amount of radioactive material
EX: 14C - up to 60,000 years238U and 40K - over 300,000 years
D. Nuclear MedicineD. Nuclear MedicineD. Nuclear MedicineD. Nuclear Medicine
Radiation Treatment larger doses are used
to kill cancerous cells in targeted organs
internal or external radiation source
Radiation treatment using-rays from cobalt-60.
D. Nuclear MedicineD. Nuclear MedicineD. Nuclear MedicineD. Nuclear Medicine
Radioisotope Tracers absorbed by specific
organs and used to diagnose diseases movie
Show DVD Isotope Tracers
E. Nuclear WeaponsE. Nuclear WeaponsE. Nuclear WeaponsE. Nuclear Weapons
Atomic Bomb chemical explosion is used to form a critical
mass of 235U or 239Pu fission develops into an uncontrolled chain
reaction
Hydrogen Bomb chemical explosion fission fusion fusion increases the fission rate more powerful than the atomic bomb
F. OthersF. OthersF. OthersF. Others
Food Irradiation radiation is used to kill bacteria
Radioactive Tracers explore chemical pathways trace water flow study plant growth, photosynthesis
Consumer Products ionizing smoke detectors - 241Am
