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Nuclear Chemistry : Radioactive Decay

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Question 1
A radioisotope decays to give an alpha particle and Pb-208. What was the original element?

Se
Bi
Po
Hg
Rn

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Question 2
Sulfur-35 decays by beta emission. The decay product is ________.

P
S
Si
35-Cl
37- Cl

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Question 3
Carbon-11 is a radioactive isotope of carbon. Its half-life is 20.3 minutes. What fraction of the initial number of C-11 atoms in a sample will remain after 81 minutes?

1/16
1/4
1/2
1/32
1/8

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Question 4
Po-208 is an alpha emitter with a half-life of 2.90 years. How many mg of polonium from an original sample of 2.0 mg will remain after 8.0 years?

0.147 mg
0.295 mg
0.725 mg
6.77 mg
1.90 mg

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Question 5
Charcoal found under a stone at Stonehenge, England, has a carbon-14 activity that is 0.60 that of new wood. How old is the charcoal? The half-life of carbon-14 is 5,730 years.

Less than 5,730 years
Between 5,730 and 11,460 years
Between 11,460 and 17,190 years
More than 17,190 years

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Question 6
What role does cadmium metal (Cd) play in a nuclear reactor?

slows down the fission neutrons (moderator)
transfers heat from the reactor to the heat exchanger (primary coolant)
controls chain reaction (control rods)
transfers heat from the condenser to the environment (cooling tower)
undergoes fission (fuel rods)

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Question 7
Which one of the following is the most penetrating of the three types of nuclear radiation?

alpha
beta
gamma

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Question 8
Gamma-rays and X-rays cause radiation damage when they interact with matter by producing ________.

ions and free radicals
isotopes
daughter products
oxidation
reduction

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Question 9
How many neutrons and protons (nucleons) does an atom with the symbol S have?

33
16
49
17
None of the above.

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Question 10
Predict the other product of the following nuclear transformation.

Li + n _____ + He

He
H
H
β
H

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Solution Summary

Nuclear chemistry and radioactive decay problems are solved. The solution is detailed and well presented.

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See Also This Related BrainMass Solution

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The reaction represented by the description "An atom of lead-210 decays by emission of an alpha particle" is:

Question 3
The reaction represented by the description "An atom of copper-66 decays by beta emission" is

Question 4
The reaction represented by the description "An atom of titanium-45 decays by positron emission" is

Question 5
The reaction represented by the description "An atom of metastable strontium-87 undergoes gamma decay" is

Question 6 T
The reaction represented by the description "An atom of selenium-75 undergoes electron capture" is

Question 7

Beta emission can best be described as

a. emission of two protons and two neutrons from an unstable nucleus.
b. transformation of a neutron into a protron and an electron that is ejected from the nucleus.
c. transformation of a proton into a neutron by combination with an electron.
d. annihilation of a beta particle by a positron.
e. annihilation of a neutrino by an anti-neutrino.

Question 8
Alpha emission can best be described as
a. emission of two protons and two neutrons from an unstable nucleus.
b. transformation of a proton into a neutron and an electron that is ejected from the nucleus.
c. transformation of a proton into a neutron by combination with an electron.
d. annihilation of a beta particle by a positron.
e. annihilation of a neutrino by an anti-neutrino.

Question 9
All of these are common modes of radioactive decay except __________.

a. alpha emission
b. beta emission
c. electron capture
d. positron emission
e. phosphorescence

Question 10
The rule that the mass number of stable isotopes is always at least twice the atomic number is true for all nuclides except

a. helium-3
b. beryllium-10
c. strontium-90
d. magnesium-28
e. vanadium-52

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