Chem- Nuclear Chemistry

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What is nuclear chemistry?
The study of changes in the NUCLEUS of an atom, one element is changed into another, radiation is emitted
Nuclear changes occur when…
subatomic particles are either added or emitted from a nucleus
Describe the amount of energy that physical, chemical, and nuclear changes yield
Physical yields a small amount, chemical yields up to 100 times that of physical, nuclear yields up to one million times that of a chemical change
Elements that undergo nuclear reactions are said to be…
What factors make a nucleus unstable?
-the proportion of protons to neutrons, if either are odd it is less stable, even numbers are the most stable
-In larger atoms more neutrons are needed to separate protons, so the ratio changes
Name the two types of decay
1) Radioactive decay/ natural decay
2) Artificial transmission(conversion of 1 element to another)
What is natural radioactivity?
Spontaneous disintegration by the emission of particles
Name the 3 types of emissions/emanations:
alpha, beta, positron
What is alpha decay?
alpha particles are ejected from the nucleus, has a mass of 4 amu, has a charge of 2+, weakest type of emission, can be blocked by a piece of paper
What is beta decay?
beta particles are ejected from the nucleus, has a mass of 0 amu, has a charge of 1-, stronger than alpha particles, can be blocked by cardboard or glass
What is positron decay?
“POSITIVE ELECTRON”, positron particles are ejected from the nucleus, has a mass of 0 amu, has a charge of 1+, same strength as beta decay, can be blocked by heavy metals, nothing thin or weak
What are gamma rays
no mass, no charge, therefore they are not particles, strongest emission, similar to x-rays, dangerous
What is a half-life?
Time it takes for 50 percent of a radioactive isotope sample to decay. Times vary from second to millenniums.
What is transmutation?
Nuclear reactions can be either naturally occurring or artificial, one element changes into another
What is induced radioactivity?
Forcing decay of a stable nucleus to occur, usually by bombarding with alpha particles or neutrons
What is the formula for conversion of mass to energy? Who came up with it?
E=mc^2 OR J-(kg)c^2
Albert Einstien
M= mass
E= Energy (eV)
c= Speed of light (3.00×10^8 m/s)
What is mass defect?
Mass that gets converted into energy
Nuclear fission
the splitting of a large nucleus to form smaller nuclei; fission=split
What are the 2 uses of nuclear fission?
1) Atomic bombs (uncontrolled fission reaction)
2) Nuclear power (controlled fission reaction)
What is a fission reactor?
A nuclear power plant
What are the parts of a fission reactor?
Fuel- usually uranium or plutonium
Moderators- slow down neutrons released (Be, water, H2)
Control Rods- absorb neutrons, slow reaction (Cd, B)
Coolant- converts heat into other energy forms (water, NA)
Shield- protects atmosphere from radiation (steel, concrete)
What is nuclear fusion?
a nuclear reaction, small nuclei combine to form a larger nucleus, occurs in star like the sun
What are advantages to nuclear fusion? What is the problem?
-More energy is produced than in fission reactions
-No toxic or radioactive waste is produced
-Fusion reactions are not yet available to produce energy on earth without being produced in a lab
What do control rods do
By raising And lowering the control rods we can increase or decrease the rate of the chain reaction by absorbing less or more neutrons (ABSORB NEUTRONS)
What do moderators do
slow neutrons down, slow reaction
what do shields do
shield outside world from radiation
Categories: Nuclear Chemistry