Nuclear Fusion and Fission (HL Option C.3 & C.7) Flashcards
what is a fusion reaction?
the fusion of hydrogen nuclei
what is the main technological issue involved in fusion?
a fusion takes place at a high temperature that it cant be contained
where does the sun’s energy come from?
hydrogen nuclei/ protons combine to form the isotope deuterium which then further combines to form helium
what is mass defect?
the difference between the mass of the nucleus and the sum of the masses of its individual nucleons
what happens to the mass defect? How can it be quantified?
it is released as energy, E=mc^2
what is an electron volt
the energy required to move one electron through a pre defined electric field
what is binding energy?
the energy required to separate a nucleus into protons and neutrons
what is the fusion of deuterium
hydrogen isotope with 1 proton and 1 neutron with tritium (hydrogen isotope with 2 neutrons) to produce helium and a neutron
what is the significance of the difference in binding energy per nucleon between helium and the 2 isotopes of hydrogen?
the nucleon are bound much more tightly in a stable helium in the nucleus, so there is a mass defect which is converted into energy
what element has the most stable nuclear configuration
iron
what is nuclear fission
elements with an atomic number greater than 92 split to form 2 lighter nuclei
what process undergoes in nuclear generated power plants
nuclear fission
What prevents chain reactions in nuclear fission?
control rods
What is critical mass?
the amount of material needed to keep the reaction sustainable such that sufficient neutrons can continue to sustain a chain reaction
What is transmutation?
conversion of one element to another by capture or emission of a particle
What is an alpha particle? What is the charge? What are the hazards?
A helium nucleus with two protons and two neutrons; +2; limited hazard unless ingested
What is a beta particle? What is the charge? What are the hazards?
High speed electron with negligible mass; -1; can burn skin
What is a gamma ray? What are the hazards?
high frequency, short wavelength electromagnetic waves, can cause cancer
What is a neutron? What is the charge? What are the hazards?
uncharged nuclear particle with mass of 1 atomic mass unit; high penetrative ability, can cause cancer
What is a positron? What is its charge?
the antiparticle of an electron, positively charged beta particle
What is a proton? What is its charge?
nuclear particle that has a mass of 1 atomic mass unit; +1
What is half life?
time it takes for one half of the atoms in a sample to decay
What order is nuclear decay?
1st order
How is radioactive waste stored? - long term
waste is encased in steel surrounded by an inert gas and covered in concrete
How are the composition of stars analyzed?
Absorption Spectra
What is the process of enriching Uranium?
diffusion or centrifugation
Why must Uranium be enriched?
only U - 235 is fissionable, however most of uranium found naturally is U - 238 so you have to enrich Uranium in order to increase the concentration of U - 235
What series of reactions converts uranium (IV) oxide to gaseous uranium hexafluoride?
UO2 + 4HF -> UF4 +2 H2O
UF4 + F2 -> UF6
Why is UF6 used more than UO2?
more volatile because of weak intermolecular forces
What is the process of diffusion to separate U - 238 and U - 235?
Gaseous UF6 is pumped through a porous membrane, because U - 235 is lighter, it diffuses faster and more easily, this has to be completed various times to ensure the isotopes have been separated
What is the process of centrifugation to separate U - 238 and U - 235?
gaseous UF6 is pumped into a centrifuge where the heaviest (U - 238) is pushed to the outside and up and the lighter (U-235) is pushed inside and out the top
What is the formula for Graham’s Law of Effusion?
(rate of effusion of gas 1) /(rate of effusion of gas 2) = (molar mass of gas 2)^.5 / (molar mass of gas 1)^.5
What are the risks associated with nuclear energy?
health risks, military applications,
What is the SI unit or ionizing radiation?
seivert
