Nuclear Chemistry

Forms of Energy The five main forms of energy are: – Heat – Chemical – Electromagnetic – Nuclear – Mechanical

Nuclear Radiation Many elements can change through radioactivity. -Radioactive elements have unstable nuclei. -Radioactive elements can decay. – Emit radiation – Can become a different isotope of the same element – Can become a different element!

Types of Radiation Alpha Particle – Helium nucleus with a + 2 charge – The largest radioactive particle – Don’t penetrate very deep Beta Particle – A fast moving electron -1 charge – Can travel through paper, but wood or aluminum will stop it. Gamma Particle – Tiny and too small to measure (like photons) – No charge – Travel through clothes and even walls

EVR3019/Nuclear_Waste.ppt

7 Alpha decay Alpha particle has a mass of protons and 2 neutrons --Mass goes down by 4 --Atomic # goes down by 2

8 Beta decay 234 Th  234 Pa + e beta particle Beta particle has a tiny mass. -- A neutron is converted to a proton --Mass stays the same --Atomic # goes up by 1

9 Gamma radiation No change in atomic or mass number 11 B 11 B + 0  boron atom in a high-energy state

Comparison of Chemical and Nuclear Reactions

RadiationComposition & Symbol Is shielded or stopped by? Alpha2 p+ and 2 n 0 paper BetaStream of high speed e- Clothing, wood GammaVery high energy electromagnetic radiation Concrete, lead

Nuclear Fission A heavy nucleus splits into more stable nuclei of intermediate mass. A heavy nucleus splits into more stable nuclei of intermediate mass.

Little Boy and Fat Man

Atomic Bombs Atomic bombs are an example of Fission Reactions. Atomic bombs are an example of Fission Reactions. “Little boy” and “Fat man” were Atomic bombs made from fission reactions with uranium and plutonium respectively. “Little boy” and “Fat man” were Atomic bombs made from fission reactions with uranium and plutonium respectively. A fission chain reaction is started and continues until the bomb destroys itself. A fission chain reaction is started and continues until the bomb destroys itself.

Nuclear Fusion Low-mass nuclei combine to form a heavier, more stable nucleus. Low-mass nuclei combine to form a heavier, more stable nucleus.

Hydrogen Bombs Hydrogen bombs are an example of nuclear fusion. Hydrogen bombs are an example of nuclear fusion. Two isotopes of hydrogen, 2 H and 3 H, fuse together and produce a lot of energy in the process. Two isotopes of hydrogen, 2 H and 3 H, fuse together and produce a lot of energy in the process. H-bombs release significantly more energy than atomic bombs. H-bombs release significantly more energy than atomic bombs.

The Sun: Nuclear Fusion Sun + + Four hydrogen nuclei (protons) Two beta particles (electrons) One helium nucleus + Energy

Comparing Fission and Fusion

Nuclear FissionNuclear Fusion

Nuclear FissionNuclear Fusion A heavy atom splits into two or more lighter nuclei Ex: Atomic Bombs & Nuclear reactors High temp and pressure are used to combine light atoms to make heavier atoms Ex: Fuels the sun and stars & Hydrogen Bombs Release huge amounts of energy Produce nuclear waste

Nuclear Power Plants map: Nuclear Energy Institute

Nuclear Power Plants Uranium-235 undergoes nuclear fission and releases thermal (heat) energy. Uranium-235 undergoes nuclear fission and releases thermal (heat) energy. This turns water to steam which spins turbines. This turns water to steam which spins turbines. The turbines produce electrical energy. The turbines produce electrical energy. Nuclear waste is fuel rods with unreacted uranium and radioactive products of fission. Nuclear waste is fuel rods with unreacted uranium and radioactive products of fission.

Did You Know ?

The time needed for one-half of the nuclei in a radioisotope to decay and emit their radiation to form a different isotope Half-timeemitted Uranium million yrsalpha, gamma Plutonium yrsalpha, gamma During operation, nuclear power plants produce radioactive wastes, including some that remain dangerous for tens of thousands of years Half-Life

Relative Doses from Radiation Sources cstl-cst.semo.edu/bornstein/BS105/ Energy%20Use%20-%203.ppt

Genetic damages: from mutations that alter genes Genetic defects can become apparent in the next generation Cellular damages: to tissue, such as burns, miscarriages & cancers Effects of Radiation