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Unit 14: Nuclear Chemistry
Transcript of Unit 14: Nuclear Chemistry
Fossils C-14 --> N-14 after ~5730 yrs Dating Rocks Rocks U-238 --> PB-206 after 4.5 billion yrs Medicinal Uses- All have a short ½ life & are eliminated from the body quickly I-131 detects thyroid disorders Tc-99 detects cancer Tl-204 & Na-24 Detects heart disease and blood flow Co-60 treats cancer & irradiates food P-31 Used in fertilizers as a tracer to detect the movement of large amounts of fertilizers. Fertilizers are used to make explosive devices. Nuclear Reactors
U-235 & Pu-239
used as fuel Heavy water is used to absorb heat. Risks Chernobyl, Ukraine
Nuclear power plant melt down
City abandoned to this day 3-Mile Island
Middletown, Pennsylvania, on March 28, 1979
Nuclear power plant leak Other risks
Illness, death from radiation poisoning
Atomic explosions Natural Transmutation Spontaneous decay of nucleus.
Emission particles are (alpha, beta, and positron. Table O REVIEW
Calculating Average Atomic Mass 99% H-1
0.2% H-3 Transmutation
A change in the nucleus from one element to another. Artificial Transmutation
When the nucleus of an atom is bombarded with high energy particles causing it to become unstable and decay. Natural Transmutation
When the nucleus of an atom is unstable due to the ratio of protons to neutrons and spontaneously decays into smaller, lighter weight elements. Control rods control the amount of “free” neutrons Fusion (Comes together)
Involves the combining of light weight nuclei to form heavier nuclei and energy Common on the Sun. Hydrogen combine to create Helium and energy.
The Problem is that it requires extremely high temperatures for nuclei to overcome repulsion and fuse. 10 billion degrees C Half Life
The time it takes for ½ of all the nuclei in a given sample to decay.
½ life is constant and stable (Not affected by pressure, temperature, or chemical combination)
Depends (assumes) the sample nuclei never reaches zero (all decayed) Example: The Decay of Radioactivnium
256g of radioactivnium
After 1 ½ life period, ____g Radioactivinium remain.
After 2 ½ life periods , ____g Radioactivinium remain.
After 3 ½ life periods , ____g Radioactivinium remain.
After 4 ½ life periods , ____g Radioactivinium remain. What is the mass of I-131 remaining 32 days after a 100g sample of the isotope is obtained?
Half-life= 8.07 days
Mass Fission (to split apart)Involves heavy weight elements such as U-235 or Pu-239
Capture of slow moving neutrons by nucleus
Makes nucleus very unstable and it decays
Produces middle weight elements, neutrons and a great deal of energy!!!!! Fukushima, Japan March 11, 2011
Magnitude 8.9 earthquake off the coast of Japan
Damaged 4 facilities, but Fukushima suffered the most damage.
There was a leak in the containment of the radioactive material. What is the original mass of I-131 if after 24 days only 6.5g of the sample remains?