nuclear chemistry - new york state regents

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By R. Frank 2014 NUCLEAR CHEMISTRY NYS REGENTS CHEMISTRY

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Page 1: Nuclear Chemistry - New York State Regents

By R. Frank 2014

NUCLEAR CHEMISTRYNYS REGENTS CHEMISTRY

Page 2: Nuclear Chemistry - New York State Regents

Radioactivity is the spontaneous disintegration of the nucleus along with the emission of particles and energy.

Nuclear reactions differ from chemical reactions in that the original atoms are changed into atoms of another element. (Photo)

INTRODUCTION TO NUCLEAR CHEMISTRY

Page 3: Nuclear Chemistry - New York State Regents

Emanations are the particles released when an element disintegrates.

EMANATIONS

Page 4: Nuclear Chemistry - New York State Regents

Penetration Power is the ability of radiation to pass through matter.

Gamma Particles have the most penetration power, and alpha particles have the least penetration power.

PENETRATING POWER

Page 5: Nuclear Chemistry - New York State Regents

On the reference tables, elements are radioactive if the atomic masses are in parentheses ( ). For example, elements with an atomic number of over 83 have atomic masses that are all in parentheses, and are therefore radioactive.

IDENTIFYING RADIOACTIVE ELMENTS

Page 6: Nuclear Chemistry - New York State Regents

Transmutations when one element is changed to another by a change in the nucleus. When an element forms an emanation (Table O), it is a natural transmutation.

An example of a natural transmutation is found below.

NATURAL TRANSMUTATIONS

Page 7: Nuclear Chemistry - New York State Regents

Artifi cial transmutations occur when a radioactive nuclei is hit with high energy particles, producing neutrons. Examples are fission and fusion.

Fission occurs when heavy nuclei are split to (usually) produce 3 extra neutrons and a lighter nuclei. (Remember, “Fission is Division”)

Fission Reaction:

Fusion occurs when two light nuclei fuse to form a heavier nucleus. (2 small atoms form 1 larger atom)

Fusion Reaction:

ARTIFICIAL TRANSMUTATIONS

Page 8: Nuclear Chemistry - New York State Regents

1. Which radioactive emanations have a charge of -1?2. Which emanation has the most penetrating power? 3-4. Identify the reactions taking place in the photo

below. Is it fusion, fission, or a natural transmutation. Why?

5. How does a nuclear reaction diff er from a chemical reaction?

6. Is the element Actinium (Ac) a radioactive element? Why or why not? Is Carbon (C) a radioactive element?

MID-UNIT COMPREHENSION CHECK

Page 9: Nuclear Chemistry - New York State Regents

Stability of an element is dependent on its ratio of protons to neutrons. An element is stable when this ratio is close to 1:1.

A half-life is the time it takes for half the atoms of a radioactive nuclide to decay. The shorter the half-life, the less stable it is.

HALF-LIFE

Page 10: Nuclear Chemistry - New York State Regents

Fissionable fuels power the reactor and include U-233, U-235, and Pu-239.

Moderators decrease the speed of neutrons, and can be heavy water, water, beryllium, or graphite.

Control rods absorb extra neutrons, and can be baron or cadmium.

Coolants keep the temperature of the reactors cool. They include water, heavy water, helium, carbon dioxide or molten lithium and sodium

NUCLEAR REACTORS

Page 11: Nuclear Chemistry - New York State Regents

NUCLEAR REACTORS

Fissionable FuelsFissionable

Fuels

Control Rods

Coolants

Page 12: Nuclear Chemistry - New York State Regents

Shielding prevents radiation leakage. External – High-density concrete. (Shown) Internal – Steel.

SHIELDING

Page 13: Nuclear Chemistry - New York State Regents

Solid and liquid radioactive wastes are encased and stored underground.

Radioactive gases are stored until they can be safely released into the environment.

DISPOSING OF RADIOACTIVE WASTE

Page 14: Nuclear Chemistry - New York State Regents

Tracers are radioactive isotopes used to follow the course of a chemical reaction.

IODINE-131 is used for thyroid disorders.

CARBON-14 is used for carbon dating of organic materials, living things, and photosynthetic reactions.

URANIUM-238 and LEAD(Pb)-206 are used for geologic dating.

TECHNICIUM (Tc) -99 is used for brain tumors.

RADON-226 and COBALT-60 are used for cancer treatments because they kill living cells.

RADIOACTIVE TRACERS

Page 15: Nuclear Chemistry - New York State Regents

Radiation is used to preserve food.

Radiation is used in medicine because of its short half-life and quick elimination.

PRACTICAL USES OF RADIOACTIVITY

R. Frank 2014