Question 1

Radium-226 decays by alpha emission. What is its decay product?

Accepted Answer

A)   
B)   
C)   
D)   
E)   F) All of the above
G) A) and B)

Question 2

The radioisotope potassium-40 decays to argon-40 by positron emission with a half-life of 1.3 * 109 yr. A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is

Accepted Answer

A)  8.1* 10-10 yr.
B)  2.4 * 109 yr.
C)  2.8 * 109 yr.
D)  4.6 * 109 yr.
E)  6.8 * 109 yr.F) All of the above
G) A) and B)

Question 3

Naturally occurring uranium contains approximately 1% U-235 and 99% U-238. Of these, the isotope that undergoes fission in a nuclear reactor is U-238.

Accepted Answer

A) True 
 B)False

Question 4

Determine how much energy is released when polonium-210 decays according to 9 kJ/mol B) 7.20 * 1011 kJ/mol C) 5.22 * 108 kJ/mol D) 4.66 * 109 kJ/mol E) 6.43 * 1012 kJ/mol" class="answers-bank-image d-inline" rel="preload" > . [Atomic masses: polonium-210 = 209.982857 amu; helium-4 = 4.002603 amu; lead-206 = 205.974449 amu]

Accepted Answer

A)  4.14 * 109 kJ/mol
B)  7.20 * 1011 kJ/mol
C)  5.22 * 108 kJ/mol
D)  4.66 * 109 kJ/mol
E)  6.43 * 1012 kJ/molF) A) and E)
G) B) and E)

Question 5

A rock contains 0.37 mg of Pb-206 and 0.95 mg of U-238. Approximately how many U-238 atoms were in the rock when it was formed billions of years ago? (The half life for 238U ? →\rarr→  206Pb is 4.5 * 109 yr.)

Accepted Answer

A)  1.32 atoms
B)  5.8 * 10-6 atoms
C)  2.4 * 1018 atoms
D)  3.5 * 1018 atoms
E)  3.5 * 1021 atoms F) C) and D)
G) All of the above

Question 6

Compare nuclear reactions with chemical reactions in terms of the conservation of mass.

Accepted Answer

As opposed to chemical reactio...

Question 7

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

Accepted Answer

A)  33
B)  16
C)  49
D)  None of the above.E) B) and C)
F) None of the above

Question 8

In the following reaction, identify X.

Accepted Answer

A)  7 β\betaβ 
B)  3 α\alphaα 
C)  4n
D)   
E)  15p F) A) and B)
G) B) and E)

Question 9

Describe the role of a moderator in a fission reactor, and give examples of two substances that are used as moderators.

Accepted Answer

Moderators slow the neutrons a...

Question 10

Tritium is a radioisotope of hydrogen having a half-life of 12.3 years. If you initially had 1.0 * 10-7 mole of tritium, calculate the decay rate of the sample.

Accepted Answer

1.08 * 10<...

Question 11

Balance the equation  .

Accepted Answer

The answer of Balance the equation  ....

Question 12

Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm) per gram of carbon. If a contemporary wooden chair were somehow preserved for the next 3,900 years, what 14C decay rate should be expected from the wood used to make the chair? (t1/2 = 5,730 yr)

Accepted Answer

A)  26 dpm
B)  12 dpm
C)  11 dpm
D)  10 dpm
E)  8 dpmF) C) and E)
G) B) and E)

Question 13

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.)

Accepted Answer

A)  Less than 5,730 yr
B)  Between 5,730 and 11,460 yr
C)  Between 11,460 and 17,190 yr
D)  More than 17,190 yrE) B) and D)
F) C) and D)

Question 14

Which type of nuclear process requires an extremely high temperature (millions of degrees) ?

Accepted Answer

A)  beta decay
B)  fission reaction
C)  fusion reaction
D)  alpha decay
E)  positron emissionF) C) and D)
G) B) and C)

Question 15

As a result of beta decay, the product nucleus is

Accepted Answer

A)  one atomic number lower than the original element.
B)  two atomic numbers higher than the original element.
C)  one atomic number higher than the original element.
D)  two atomic numbers lower than the original element.
E)  four atomic numbers lower than the original element.F) All of the above
G) C) and E)

Question 16

Predict which nucleus is less stable,  or  .

Accepted Answer

The answer of Predict which nucleus is less stable, ...

Question 17

The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm) per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t1/2 = 5,730 yr)

Accepted Answer

A)  6,800 yr
B)  2,500 yr
C)  4,700 yr
D)  10,000 yr
E)  7,200 yrF) A) and E)
G) A) and D)

Question 18

Cobalt-60 is a beta emitter with a half-life of 5.3 years. Approximately what fraction of cobalt-60 atoms will remain in a particular sample after 26.5 years?

Accepted Answer

A)  1/5
B)  1/16
C)  1/26
D)  1/32
E)  1/64F) A) and D)
G) All of the above

Question 19

Balance the equation  .

Accepted Answer

The answer of Balance the equation  ....

Question 20

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

Accepted Answer

A)  1/16
B)  1/4
C)  1/2
D)  1/32
E)  1/8F) All of the above
G) C) and E)

Exam 21: Nuclear Chemistry

Which type of nuclear process requires an extremely high temperature (millions of degrees) ?

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

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

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Naturally occurring uranium contains approximately 1% U-235 and 99% U-238. Of these, the isotope that undergoes fission in a nuclear reactor is U-238.

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Tritium is a radioisotope of hydrogen having a half-life of 12.3 years. If you initially had 1.0 * 10-7 mole of tritium, calculate the decay rate of the sample.

Correct Answerverified1.08 * 10<...View AnswerShow Answer

Balance the equation .

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Radium-226 decays by alpha emission. What is its decay product?

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The radioisotope potassium-40 decays to argon-40 by positron emission with a half-life of 1.3 * 109 yr. A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is

Correct AnswerverifiedShow Answer

Balance the equation .

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Describe the role of a moderator in a fission reactor, and give examples of two substances that are used as moderators.

Correct AnswerverifiedModerators slow the neutrons a...View AnswerShow Answer

The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm) per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t1/2 = 5,730 yr)

Correct AnswerverifiedShow Answer

In the following reaction, identify X.

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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.)

Correct AnswerverifiedShow Answer

Predict which nucleus is less stable, or .

Correct AnswerverifiedShow Answer

Cobalt-60 is a beta emitter with a half-life of 5.3 years. Approximately what fraction of cobalt-60 atoms will remain in a particular sample after 26.5 years?

Correct AnswerverifiedShow Answer

Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm) per gram of carbon. If a contemporary wooden chair were somehow preserved for the next 3,900 years, what 14C decay rate should be expected from the wood used to make the chair? (t1/2 = 5,730 yr)

Correct AnswerverifiedShow Answer

Determine how much energy is released when polonium-210 decays according to . [Atomic masses: polonium-210 = 209.982857 amu; helium-4 = 4.002603 amu; lead-206 = 205.974449 amu]

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A rock contains 0.37 mg of Pb-206 and 0.95 mg of U-238. Approximately how many U-238 atoms were in the rock when it was formed billions of years ago? (The half life for 238U ? →\rarr→ 206Pb is 4.5 * 109 yr.)

Correct AnswerverifiedShow Answer

As a result of beta decay, the product nucleus is

Correct AnswerverifiedShow Answer

Compare nuclear reactions with chemical reactions in terms of the conservation of mass.

Correct AnswerverifiedAs opposed to chemical reactio...View AnswerShow Answer

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Correct Answer
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Correct Answer
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Tritium is a radioisotope of hydrogen having a half-life of 12.3 years. If you initially had 1.0 * 10^-7 mole of tritium, calculate the decay rate of the sample.

Correct Answer
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1.08 * 10<...
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Correct Answer
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Correct Answer
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The radioisotope potassium-40 decays to argon-40 by positron emission with a half-life of 1.3 * 10⁹ yr. A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is

Correct Answer
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Correct Answer
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Correct Answer
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Moderators slow the neutrons a...
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The carbon-14 activity of some ancient Indian corn was found to be 7.0 disintegrations per minute (dpm) per gram of carbon. If present-day plant life has 16 dpm per gram of carbon, how old is the Indian corn? (t_1/2 = 5,730 yr)

Correct Answer
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In the following reaction, identify X. $In the following reaction, identify X. A) 7 \beta B) 3 \alpha C) 4n D) E) 15p$

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Present-day plant life has a carbon-14 decay rate of 16 disintegrations per minute (dpm) per gram of carbon. If a contemporary wooden chair were somehow preserved for the next 3,900 years, what ¹⁴C decay rate should be expected from the wood used to make the chair? (t_1/2= 5,730 yr)

Correct Answer
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Correct Answer
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A rock contains 0.37 mg of Pb-206 and 0.95 mg of U-238. Approximately how many U-238 atoms were in the rock when it was formed billions of years ago? (The half life for ²³⁸U ? $\rarr$ ²⁰⁶Pb is 4.5 * 10⁹ yr.)

Correct Answer
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Correct Answer
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Correct Answer
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As opposed to chemical reactio...
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