Deck 21: Nuclear Chemistry

Question 1

In the uranium-238 decay series there are eight radioisotopes starting with that decay by alpha emission, and six radioisotopes that decay by beta emission. The final product of this series is a stable isotope. The symbol for this product is

A) .
B) .
C) .
D) .
E)none of these.

Answer 1

.

Question 2

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

A)Se
B)Bi
C)Po
D)Hg
E)Rn

Answer 2

Po

Question 3

Find the nuclear binding energy of potassium-40 (atomic mass = 39.9632591 amu)in units of joules per nucleon. [Data: neutron mass = 1.674928 * 10^-24 g; proton mass = 1.672623 * 10^-24g; electron mass = 9.109387 * 10^-28 g; N_A = 6.0221367 * 10²³ /mol; c = 2.99792458 * 10⁸ m/s]

A)1.37 *0 10^-12 J/nucleon
B)5.48 * 10^-11 J/nucleon
C)5.64 * 10^-11 J/nucleon
D)1.41 * 10^-12 J/nucleon
E)2.97 * 10^-12 J/nucleon

Answer 3

1.37 *0 10^-12 J/nucleon

Question 4

When atoms of aluminum-27 are bombarded with alpha particles, a neutron and an element are produced. The particular isotope formed is

A)
B)
C)
D)
E)

Question 5

When atoms of beryllium-9 are bombarded with alpha particles, neutrons are produced. What new isotope is also formed?

A)
B)
C)
D)
E)

Question 6

As a result of beta decay, the product nucleus is

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.

Question 7

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

A) .
B) .
C) .
D) .
E) .

Question 8

In the decay series there are six radioisotopes that decay by alpha emission, including Th-232 itself, and four radioisotopes that decay by beta emission. The final product of this series is a stable isotope. The symbol for this product is

A) .
B) .
C) .
D) .
E) .

Question 9

What is the missing symbol in this plutonium fission reaction?

A)
B)
C)
D)
E)

Question 10

The energy equivalent of 1 amu is

A)5.0 * 10^-19 J.
B)5.4 * 10⁴³ J.
C)6.6 * 10⁹ J.
D)1.5 * 10^-10 J.

Question 11

What is the nuclear binding energy per nucleon, in joules, for (atomic mass 24.985839 amu). [Data: (atomic mass)= 1.007825 amu; (mass)= 1.008665 amu; 1 kg = 6.022 * 10²⁶ amu; c = 3.00 * 10⁸ m/s]

A)0.22076 J/nucleon
B)3.30 * 10^-11 J/nucleon
C)1.32 * 10^-12 J/nucleon
D)0.999 J/nucleon
E)None of the above.

Question 12

Predict the other product of the following nuclear transformation.

A)
B)
C)
D)
E)

Question 13

Alpha particles are identical to

A)protons.
B)helium atoms.
C)hydrogen atoms.
D)helium nuclei.
E)electrons.

Question 14

The isotope with the greatest nuclear binding energy per nucleon is

A) .
B) .
C) .
D) .
E) .

Question 15

Beta particles are identical to

A)protons.
B)helium atoms.
C)hydrogen atoms.
D)helium nuclei.
E)electrons.

Question 16

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

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

Question 17

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

A)
B)
C)
D)
E)

Question 18

The only stable isotope of iodine is iodine-127. Predict the mode of decay of .

A)alpha emission
B)beta emission
C)positron emission
D)electron capture

Question 19

The only stable isotope of aluminum is aluminum-27. What type of radioactive decay should be expected from ?

A)
B)
C)
D)
E)

Question 20

A typical radius of an atomic nucleus is about

A)100 µm.
B)5000 mm.
C)100 nm.
D)5 * 10^-3 pm.
E)500 pm.

Question 21

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]

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/mol

Question 22

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?

A)1/16
B)1/4
C)1/2
D)1/32
E)1/8

Question 23

Charcoal samples taken from holes dug at Stonehenge, England, have a carbon-14 specific activity of 9.50 dpm per gram carbon. Living wood has a specific activity of 15.3 dpm per gram of carbon. Given that the half-life of carbon-14 is 5730 yr, how long ago was the wood part of a living plant?

A)3940 yr
B)3550 yr
C)9230 yr
D)5700 yr
E)13300 yr

Question 24

A rock contains 0.37 mg of Pb-206 and 0.95 mg of U-238. The half-life of the decay series U-238 $\rarr$ Pb-206 is 4.5 *10⁹ yr. Assuming no Pb-206 was present in the rock initially, how old is the rock?

A)1.7 * 10⁹ yr
B)5.2 * 10⁹ yr
C)2.7 * 10⁶ yr
D)4.5 * 10⁹ yr
E)2.4 * 10⁹ yr

Question 25

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?

A)1/5
B)1/16
C)1/26
D)1/32
E)1/64

Question 26

Determine how much energy is released when thorium-230 decays according to . [Atomic masses: thorium-230 = 230.033127 amu; helium-4 = 4.002603 amu; radium-226 = 226.025403 amu]

A)3.98 * 10⁹ kJ/mol
B)4.60 * 10⁸ kJ/mol
C)7.20 * 10¹¹ kJ/mol
D)4.90 * 10⁹ kJ/mol
E)7.15 * 10¹¹ kJ/mol

Question 27

Find the nuclear binding enrgy of uranium-234 (atomic mass = 234.040947 amu)in units of joules per nucleon. [Data: neutron mass = 1.674928 * 10^-24 g; proton mass = 1.672623 * 10^-24 g; electron mass = 9.109387 * 10^-28 g; N_A = 6.0221367 * 10²³ /mol; c = 2.99792458 * 10⁸ m/s]

A)2.97 * 10^-10 J/nucleon
B)3.04 * 10^-10 J/nucleon
C)1.30 * 10^-12 J/nucleon
D)1.22 * 10^-12 J/nucleon
E)1.27 * 10^-12 J/nucleon

Question 28

Calculate the energy released in joules when one mole of polonium-214 decays according to the equation [Atomic masses: Pb-210 = 209.98284 amu, Po-214 = 213.99519 amu, He-4 = 4.00260 amu.]

A)8.78 * 10¹⁴ J/mol
B)7.2 * 10¹⁴ J/mol
C)8.78 * 10¹¹ J/mol
D)-9.75 * 10^-3 J/mol
E)1.46 * 10^-9 J/mol

Question 29

The half-life of ⁹⁰Sr is 29 years. What fraction of the atoms in a sample of ⁹⁰Sr would remain 175 years later?

A)0.17
B)0.12
C)0.062
D)0.015
E)0.50

Question 30

Cobalt-60 is a beta emitter with a half-life of 5.3 years. Approximately what fraction of the cobalt-60 atoms in a particular sample will remain after 32 years?

A)1/6
B)1/8
C)1/16
D)1/32
E)1/64

Question 31

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.)

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

Question 32

The ¹⁴C activity of some ancient Peruvian corn was found to be 10 disintegrations per minute per gram of carbon. If present-day plant life shows 15 dpm/g, how old is the Peruvian corn? The half-life of ¹⁴C is 5730 yr.

A)1,455 yr
B)1,910 yr
C)3,350 yr
D)3,820 yr
E)9,080 yr

Question 33

What fraction of radioactive atoms remains in a sample after six half-lives?

A)zero
B)1/6
C)1/16
D)1/32
E)1/64

Question 34

The only stable isotope of fluorine is . What type of radioactivity would you expect from the isotope , which has one fewer neutron?

A)
B)
C)
D)
E)

Question 35

How old is a bottle of wine if the tritium (³H)content is 25% that of a new wine? The half-life of tritium is 12.5 years.

A)0.25 yr
B)3.1 yr
C)25 yr
D)38 yr
E)50. yr

Question 36

The heaviest known isotope of hydrogen is called tritium, . It decays by beta emission, and has a half-life of 12.3 years. What fraction of a tritium sample will remain after 5.20 years ?

A)0.0210
B)0.746
C)3.41
D)0.254
E)0.423

Question 37

Estimate the age of a bottled wine that has a tritium, ³H, content 60% that of freshly bottled wine. Tritium decays by beta decay and has a half-life of 12.3 yr.

A)0.029 yr
B)7.4 yr
C)9.1 yr
D)16 yr
E)35 yr

Question 38

Polonium-208 is an alpha emitter with a half-life of 2.90 years. How many milligrams of polonium from an original sample of 2.00 mg will remain after 8.00 years?

A)0.147 mg
B)0.296 mg
C)0.725 mg
D)6.77 mg
E)1.90 mg

Question 39

If 12% of a certain radioisotope decays in 5.2 years, what is the half-life of this isotope?

A)0.59 yr
B)1.7 yr
C)22 yr
D)28 yr
E)32 yr

Question 40

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.)

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 yr

Question 41

What would the atom ratio of ²⁰⁶Pb to ²³⁸U be in a uranium mineral from a rock that is 1.0 * 10⁹ years old? t_1/2(²³⁸U)= 4.5 * 10⁹ yr.

A)0.14
B)0.16
C)0.22
D)0.86
E)1.16

Question 42

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)

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

Question 43

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)

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

Question 44

The half-life of ¹⁴C is 5,730 yr. Assuming some charcoal from a campfire 29,000 years old was found, what fraction of the original C-14 would remain today?

A)3.0 * 10^-2
B)0.197
C)3.51
D)33.3
E)None of these.

Question 45

Petroleum is a fossil fuel containing many different carbon compounds. If the carbon atoms in petroleum have been in the ground for 100 million years, what fraction of the initial ¹⁴C atoms is still there? (t_1/2 = 5,370 yr)

A)0
B)1 * 10^-10
C)5.7 * 10^-5
D)1.0 * 10^-3
E)5.7 * 10^-1

Question 46

Which one of the following statements about fission and fusion is false?

A)Fission occurs among the heaviest isotopes, whereas fusion occurs more readily for light isotopes.
B)For a fission reaction the mass defect ( $\Delta$ m)is negative, whereas for fusion $\Delta$ m is positive.
C)In order for fusion reactions to occur, temperatures must be in the millions of degrees.
D)The fission of Pu-239 atoms produces a great number of isotopes of a large number of elements.
E)Neutron-induced fission processes can occur at room temperature, rather than at millions of degrees.

Question 47

Which of the following is an advantage of nuclear power plants over coal-burning plants? Nuclear power plants

A)produce radioactive byproducts with very short half-lives, reducing the need for waste storage.
B)do not pollute the air with SO₂, soot, and fly-ash.
C)create no thermal pollution.
D)generate radioactive byproducts that can be sold for use in secondary applications.

Question 48

The energy released by the sun is the result of

A)natural radioactivity.
B)nuclear fusion.
C)combustion of hydrogen.
D)photosynthesis.
E)nuclear fission.

Question 49

Rubidium-87 decays by beta decay with a half-life of 4.9 * 10¹⁰ yr. How many ⁸⁷Rb atoms are in a moon rock sample that has a rubidium decay rate of 3,500 disintegrations per hour?

A)9.0 * 10¹⁶ atoms
B)4.3 * 10^-4 atoms
C)2.2 * 10¹⁸ atoms
D)2.5 * 10¹⁴ atoms
E)1.7 * 10¹⁴ atoms

Question 50

The Rb-87/Sr-87 method of dating rocks is often used by geologists: t_1/2 = 6.0 * 10¹⁰ yr Estimate the age of a rock sample in which the present-day mole ratio of Rb-87 to Sr-87 is 36:1.

A)2.4 * 10⁹ yr
B)1.7 * 10⁹ yr
C)3.1 * 10¹¹ yr
D)4.1 * 10^-11 yr
E)3.6 * 10¹¹ yr

Question 51

What element is the stable end-product of the uranium radioactive decay series?

A)Th
B)Pu
C)Ra
D)Au
E)Pb

Question 52

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

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.

Question 53

Which is the most penetrating of the three types of nuclear radiation?

A)alpha
B)beta
C)gamma

Question 54

The dose unit of ionizing radiation is called the rad. The rad is defined in terms of

A)the half-life of a radioisotope.
B)the energy deposited per gram of an object.
C)the biological damage produced.
D)the accumulation of fission products.
E)the number of ions per centimeter.

Question 55

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

A)beta decay
B)fission reaction
C)fusion reaction
D)alpha decay
E)positron emission

Question 56

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

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

Question 57

A sample of a radioisotope shows an activity of 999 disintegrations per minute due to beta decay. If after 1.10 years the activity is 952 disintegrations per minute, what is the half-life of this radioisotope?

A)4.38 * 10^-2 yr
B)11.4 yr
C)0.25 yr
D)15.8 yr
E)9.1 yr

Question 58

Which type of radiation is the least penetrating?

A)alpha
B)beta
C)gamma

Question 59

Gamma-rays cause radiation damage when they interact with matter by producing

A)ions and free radicals.
B)isotopes.
C)daughter products.
D)oxidation.
E)reduction.

Question 60

In passing through matter, alpha particles lose energy chiefly by causing

A)fermentation.
B)neutralization.
C)ionization.
D)condensation.
E)carbonation.

Question 61

Which isotope, when bombarded with oxygen-18, yields the artificial isotope seaborgium-263 plus 4 neutrons?

A)nobelium-245
B)radium-259
C)californium-245
D)nobelium-249
E)californium-249

Question 62

Complete and balance the nuclear equation .

Question 63

Which isotope, when bombarded with nitrogen-15, yields the artificial isotope dubnium-260 plus 4 neutrons?

A)californium-245
B)thorium-257
C)nobelium-245
D)californium-249
E)dubnium-249

Question 64

On a plot of the number of neutrons versus the number of protons, a nucleus of aluminum-28 lies above the belt of stability. Write an equation for radioactive decay of aluminum-28.

Question 65

What is the decay rate of a sample of a radioisotope that has an activity of 12 microcuries? [1 curie = 3.7 * 10¹⁰ disintegrations/s]

Question 66

On a neutron number versus proton number plot, the nucleus of oxygen-15 lies below the
belt of stability. Write an equation for radioactive decay of oxygen-15.

Question 67

Decay of tin-110 by electron capture yields

A)tin-109.
B)cadmium-106.
C)indium-110.
D)antimony-110.
E)tellurium-114.

Question 68

In the following reaction, identify X.

A)
B)
C)
D)
E)

Question 69

Decay of lutetium-167 by electron capture yields

A)ytterbium-167.
B)lutetium-166.
C)thulium-163.
D)tantalum-171.
E)hafnium-167.

Question 70

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.

Question 71

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, how many moles of tritium would be left after 78 years?

Question 72

Complete and balance the nuclear equation .

Question 73

In the following reaction, identify X.

A)( $\alpha$ )
B)n
C)p
D)
E)( $\beta$ )

Question 74

Decay of silicon-27 by positron emission yields

A)magnesium-23.
B)sulfur-31.
C)phosphorus-27.
D)silicon-26.
E)aluminum-27.

Question 75

Decay of ruthenium-93 by positron emission yields

A)technetium-93.
B)molybdenum-89.
C)palladium-97.
D)rhenium-93.
E)ruthenium-92.

Question 76

In the following reaction, identify X.

A)7 $\beta$
B)3 $\alpha$
C)4n
D)
E)15p

Question 77

Complete and balance the nuclear equation .

Question 78

How many ¹⁴C atoms are in a charcoal sample that has a decay rate of 3,500 disintegrations per min? (For ¹⁴C, t_1/2 = 5,730 yr.)

A)2.9 * 10⁷ atoms
B)8.0 * 10^-7 atoms
C)1.4 * 10¹⁴ atoms
D)1.5 * 10¹³ atoms
E)6.02 * 10²⁰ atoms

Question 79

Complete and balance the nuclear equation .

Question 80

Complete and balance the nuclear equation .