KEY - RADIATION REVIEW

  1. 5 types of radiation: alpha particle, beta particle, gamma ray, neutron, proton
  2. Nuclear Chemistry:
  3. C) Becquerel
  4. The blanks are DECAY and STABLE
  5. GREATER
  6. Half-life
  7. What is half life?

The amount of time it takes for half of the mass of a radioactive element to decay.

  1. A)
  2. Why is it beneficial that different substances have different half lives?

Radioactive dating – allows us to accurately date samples that are thousands of years old, as well as samples that are millions of years old.

  1. Fission
  2. What is fission?

Splitting of nucleii

  1. The blank is CHAIN
  1. What are the key “things” that keep fission going?

neutrons

  1. Which element was used in the atomic bomb named “Little Boy?”

Uranium

  1. What is “Critical mass?”

Minimum mass of a radionuclide required to sustain a chain reaction

  1. Why did scientists begin creation of the atomic bomb in the first place?

To develop something so powerful that its threat could end all wars.

  1. Nuclear reactors
  2. What is the purpose of a nuclear reactor? (What does it do?)

To split atoms and therefore generate tremendous amounts of energy.

  1. What do the control rods do? How do they do the “controlling?”

To absorb neutrons, and therefore slow or speed up the fission reaction

  1. What do you do with the control rods if you want to increase fission?

Take them out of the core

  1. What do you do with the control rods if you want to decrease fission?

Push them back into the core

  1. Chernobyl
  2. Why did people die right away after Chernobyl exploded?

Blast of the explosion; massive doses of radiation

  1. How did radiation reach 20 other countries?

It was carried by the wind; it even traveled up into the jet stream

c. GEIGER COUNTER

  1. Fusion
  2. What is fusion?

Nuclei combining

  1. Where does fusion commonly take place?

Stars (i.e. our sun)

  1. Write balanced nuclear equations for the following reactions:
  2. Radium-223 undergoes alpha decay
  1. Carbon-14 undergoes negative beta decay

c. ALPHA PARTICLE

  1. The half-life of cesium-137 is 30.2 years. If the initial mass of a sample of cesium-137 is 1.00 kg, how much will remain after 151 years?

SAME AS THE FIRST PROBLEM ON THE HALF-LIFE WS WE DID IN CLASS

151 yrs / 30.2 = 5 half lives passed

1.0kg .5kg .25kg .125 kg 0.0625 kg 0.03125 kg

  1. EACH HALF LIFE is 4 DAYS and you need to get to 1/16th of the original amount. We don’t know the original amount, so let’s call is x

0  4 days = ½ of x

4  8 days = ½ of ½ of x = ¼ of x

8  12 days = ½ of ¼ of x = 1/8 of x

12  16 days = ½ of 1/8 of x = 1/16 of x

IT TAKES 16 days to get to 1/16th of the original amount (x)