Chemistry Matter and Change

Thandi Buthelezi, Laurel Dingrando, Nicholas Hainen Cheryl Wistrom, Dinah Zike

Chapter 24

Nuclear Chemistry - all with Video Answers

Educators

+ 19 more educators

Chapter Questions

Problem 1

A List the different types of radiation and their charges

Amy Jiang

Amy Jiang

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Problem 2

. Compare the subatomic particles involved in nuclear and chemical reaction

Madi Sousa

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Problem 3

Explain how you know whether the reaction is chemical or nuclear when an atom undergoes a reaction and attains a more-stable form.

Arun Bana

Numerade Educator

Problem 4

Calculate Table 24.2 gives approximate energy values in units of MeV. Convert each value into joules using the following conversion factor $1 \mathrm{MeV}=1.6 \times 10^{-13} \mathrm{J}$

Madi Sousa

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Problem 5

Summarize Make a time line that summarizes the major events that led to the understanding of alpha, beta, and gamma radiation.

Anupam Ojha

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Problem 6

Write a balanced nuclear equation for the reaction in which oxygen-15 undergoes positron emission.

Shreestika Pradhan

Shreestika Pradhan

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Problem 7

Thorium-229 is used to increase the lifetime of fluorescent bulbs. What type of decay occurs when thorium-229 decays to form radium-225?

Ronald Prasad

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Problem 8

Challenge The figure at right shows one way that bismuth-212 can decay, producing isotopes A and B.
a. Write a balanced nuclear equation for this decay.
b. Identify the isotopes $A$ and $B$ that are produced.

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 9

Bandages can be sterilized by exposure to gamma radiation from cobalt-60, which has a half-life of 5.27 y. How much of a 10.0-mg sample of cobalt-60 is left after one half-life? Two half-lives? Three half-lives?

Madi Sousa

Numerade Educator

Problem 10

If the passing of five half-lives leaves 25.0 mg of a strontium-90 sample, how much was present in the beginning?

Matthew Confer

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Problem 11

Challenge The table shows the amounts of radioisotopes in three different samples. To the nearest gram, how much will be in Sample B and Sample C when Sample A has 16.2 g remaining?

Amy Jiang

Numerade Educator

Problem 12

A Describe what happens to unstable nuclei.

Matthew Lueckheide

Matthew Lueckheide

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Problem 13

Explain how you can predict whether or not an isotope is likely to be stable if you know its number of neutrons and protons.

Amy Jiang

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Problem 14

Describe the forces acting on the particles within a nucleus and explain why neutrons are the glue holding the nucleus together.

Matthew Confer

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Problem 15

Predict the nuclear equation for the alpha decay of radium-226 used on the tips of older lightning rods.

Madi Sousa

Numerade Educator

Problem 16

Calculate how much of a 10.0-g sample of americium-241 remains after four half-lives. Americium-241 is a radioisotope commonly used in smoke detectors and has a half-life of 430 y.

KR

Karli Redwine

Numerade Educator

Problem 17

Calculate After 2.00 y, 1.986 g of a radioisotope remains from a sample that had an original mass of 2.000 $\mathrm{g}$ .
a. Calculate the half-life.
b. How much of the radioisotope remains after 10.00 y?

Ronald Prasad

Numerade Educator

Problem 18

Graph A sample of polonium-214 originally has a mass of 1.0 g. Express the mass remaining as a percent of the original sample after a period of one, two, and three half-lives. Graph the percent remaining versus the number of half-lives. Approximately how much time has elapsed when 20% of the original sample remain?

Lottie Adams

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Problem 19

Write the balanced nuclear equation for the induced transmutation of aluminum-27 into sodium-24 by neutron bombardment. An alpha particle is released in the reaction.

David Collins

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Problem 20

Write the balanced nuclear equation for the alpha-particle bombardment of $_{94}^{239} \mathrm{Pu}$ . One of the reaction products is a neutron.

Madi Sousa

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Problem 21

Challenge Archeologists sometimes use a procedure called neutron activation analysis to identify elements in artifacts. The figure at right shows one type of reaction that can occur when an artifact is bombarded with neutrons. If the product of the process is cadmium-110, what was the target and unstable isotope? Write balanced nuclear equations for the process to support your answer.

David Collins

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Problem 22

Compare and contrast nuclear fission and nuclear fusion reactions. Describe the particles that are involved in each type of reaction and the changes they undergo.

Matthew Confer

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Problem 23

Describe the process that occurs during a nuclear chain reaction and explain how to monitor a chain reaction in a nuclear reactor.

Amy Jiang

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Problem 24

Explain how nuclear fission can be used to generate electric power.

Matthew Confer

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Problem 25

Formulate an argument supporting or opposing nuclear power as your state’s primary power source. Assume the primary source of power currently is the burning of fossil fuels.

Madi Sousa

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Problem 26

Calculate What is the energy change $(\Delta E)$ associated with a change in mass $(\Delta m)$ of 1.00 $\mathrm{mg}$ ?

David Collins

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Problem 27

Interpret Graphs Use the graph in Figure 24.14 on page 877 to answer the following questions.
a. Why is the isotope $_{26}^{56}$ Fe highest on the curve?
b. Are more stable isotopes located higher or lower on the curve?
c. Compare the stability of Li- 6 and $\mathrm{He}-4$ .

Jennifer Hudspeth

Jennifer Hudspeth

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Problem 28

Explain one way in which nuclear chemistry is used to diagnose or treat disease.

Matthew Confer

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Problem 29

Describe several methods used to detect and measure radiation.

Amy Jiang

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Problem 30

Compare and contrast somatic and genetic biological damage

Madi Sousa

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Problem 31

Explain why it is safe to use radioisotopes to diagnose medical problems

Matthew Confer

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Problem 32

Calculate A lab worker receives an average radiation dose of 21 mrem each month. Her allowed dose is 5,000 mrem/y. On average, what fraction of her yearly dose does she receive?

Madi Sousa

Numerade Educator

Problem 33

Interpret Data Look at the data in Table 24.7. Suppose someone is exposed to the maximum values listed for average annual radiation from the ground, from buildings, and from the air. What fraction would the person receive of the minimum dose (25 rem) that causes a temporary decrease in white blood cell
population?

David Collins

Numerade Educator

Problem 34

Compare and contrast chemical reactions and nuclear reactions in terms of energy changes and the particles involved.

Matthew Confer

Numerade Educator

Problem 35

Match each numbered choice on the right with the correct radiation type on the left
$$
\begin{array}{ll}{\text { a. alpha }} & {\text { 1. high-speed electrons }} \\ {\text { b. beta }} & {\text { 2. } 2+\text { charge, blocked easily }} \\ {\text { c. gamma }} & {\text { 3. no charge, electromagnetic radiation }}\end{array}
$$

Madi Sousa

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Problem 36

Figure 24.30 shows alpha particles, beta particles, and gamma rays passing through a screen and between two charged plates. What can you infer about the identity of a, b, and c? Explain your answer

Matthew Confer

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Problem 37

What is the difference between X rays and gamma rays?

Amy Jiang

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Problem 38

Dental crown Uranium-234 is used to make dental crowns appear brighter. The alpha decay of uranium234 produces what isotope?

Madi Sousa

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Problem 39

Detecting Material Flaws Flaws in welded metal parts of airplanes can be identified by placing the isotope iridium-192 on one side of the weld and photographic film on the other side to detect gamma rays that pass through. How does the gamma ray emission affect the atomic number and mass number of the iridium?

Madi Sousa

Numerade Educator

Problem 40

Colored Glass Thorium-230 can be used to provide coloring in glass objects. One method of producing
thorium-230 is through the radioactive decay of actinium-230. Is this an example of alpha decay or beta
decay? How do you know?

Matthew Confer

Numerade Educator

Problem 41

Plastic Bags Thin sheets of plastic are used to make items such as grocery bags. The sheets move under a source of promethium-147, emitting beta particles. The radiation intensity, measured under the plastic sheets, is used to monitor the thickness of the plastic. During this process, promethium changes into which element?

Sarah Ganrude

Numerade Educator

Problem 42

What is the strong nuclear force? On which particles does it act?

Matthew Confer

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Problem 43

Explain the difference between positron emission and electron capture.

Amy Jiang

Numerade Educator

Problem 44

Categorize each type of radioactive decay.
a. Mass number and atomic number are unchanged.
b. Mass number remains the same and atomic number decreases.

Aparna Shakti

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Problem 45

What is the significance of the band of stability?

Amy Jiang

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Problem 46

What is a radioactive decay series? When does it end?

Matthew Confer

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Problem 47

Radioisotopes What are the factors that determine the amount of a given radioisotope in nature?

David Collins

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Problem 48

In which region(s) in Figure 24.31 are you likely to find
a. stable nucle?
b. nuclei that undergo alpha decay?
c. nuclei that undergo beta decay?
d. nuclei that undergo positron emission?

Madi Sousa

Numerade Educator

Problem 49

Carbon-14 Dating Carbon-14 dating makes use of a specific ratio of two different radioisotopes. Define the ratio used in carbon-14 4 dating. Why is this ratio constant in living organisms?

Madi Sousa

Numerade Educator

Problem 50

Calculate the neutron-to-proton ratio for each atom
a. $\operatorname{tin}-134$
b. silver-107
c. carbon- 12
d. carbon- 14

Madi Sousa

Numerade Educator

Problem 51

Complete the following equations.
$$a.\quad_{83}^{214} \mathrm{Bi} \rightarrow_{2}^{4} \mathrm{He}+?$$
$$b.\quad_{93}^{239} \mathrm{Np} \rightarrow_{94}^{239} \mathrm{Pu}+?$$

Madi Sousa

Numerade Educator

Problem 52

Write a balanced nuclear equation for the alpha decay of americium-241.

Matthew Confer

Numerade Educator

Problem 53

Write a balanced nuclear equation for the beta decay of cesium-137.

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 54

Bone Formation The electron capture of strontium-85 can be used by physicians to study bone formation. Write a balanced nuclear equation for this reaction.

Matthew Confer

Numerade Educator

Problem 55

Nuclear mishap The half-life of tritium $\left(_{1}^{3} \mathrm{H}\right)$ is 12.3 $\mathrm{y}$ If 48.0 $\mathrm{mg}$ of tritium is released from a nuclear power plant during the course of a mishap, what mass of the nuclide will remain after 49.2 $\mathrm{y} ?$ After 98.4 $\mathrm{y} ?$

Madi Sousa

Numerade Educator

Problem 56

Static Charge Static charge can interfere with the production of plastic products by attracting dust and dirt. To reduce it, manufacturers expose the area to polonium-210, which has a half-life of 138 days. How much of a 25.0-g sample will remain after one year (365 days)?

Ronald Prasad

Numerade Educator

Problem 57

The half-life of polonium-218 is 3.0 min. If you start with 20.0 g, how long will it be before only 1.0 g
remains?

David Collins

Numerade Educator

Problem 58

An unknown radioisotope exhibits 8540 decays per second. After 350.0 min, the number of decays has
decreased to 1250 per second. What is the half-life?

Matthew Confer

Numerade Educator

Problem 59

Define transmutation. Are all nuclear reactions also transmutation reactions? Explain.

Amy Jiang

Numerade Educator

Problem 60

Relate binding energy per nucleon to mass number

Matthew Confer

Numerade Educator

Problem 61

Referring to Figure $24.7,$ would you expect $_{20}^{39} \mathrm{Ca}$ to be radioactive? Explain.

Madi Sousa

Numerade Educator

Problem 62

What is a chain reaction? Give an example of a nuclear chain reaction.

Matthew Confer

Numerade Educator

Problem 63

Explain the purpose of control rods in a nuclear reactor.

Amy Jiang

Numerade Educator

Problem 64

Why is the fuel of a nuclear reactor enriched?

Matthew Confer

Numerade Educator

Problem 65

Describe what is meant by the terms critical mass, subcritical mass, and supercritical mass. Which is
shown in Figure 24.32? How can you tell?

Amy Jiang

Numerade Educator

Problem 66

Explain how it is possible that fission, the splitting of nuclei, and fusion, the combining of nuclei, both release tremendous amounts of energy.

Matthew Confer

Numerade Educator

Problem 67

Describe the current limitations of fusion as a power source.

Amy Jiang

Numerade Educator

Problem 68

Why does nuclear fusion require so much heat? How is heat contained within a tokamak reactor?

Matthew Confer

Numerade Educator

Problem 69

Smoke Detectors Americium-241, a radioisotope used in smoke detectors, is produced by bombarding plutonium-238 with neutrons to produce plutonium-240, which is bombarded with neutrons to produce plutonium-241. The plutonium-241 decays to americium-241. Write the balanced nuclear equations for each reaction.

Madi Sousa

Numerade Educator

Problem 70

Exit signs Exit signs are coated with a paint containing phosphors. These phosphors are activated by the radioisotope tritium $\left(\begin{array}{l}{3} \\ {1}\end{array} \mathrm{H}\right)$ produced by bombarding lithium-6 with neutrons to produce lithium- $7 .$ The lithium- 7 then undergoes alpha decay to produce the tritium. Write balanced nuclear equations for both steps.

Madi Sousa

Numerade Educator

Problem 71

Control Rods Bombarding uranium-235 with neutrons produces samarium-149, which is used in nuclear reactor control rods. What other element is produced?

Vasu Makani

Numerade Educator

Problem 72

The Sun $_{1}^{1} \mathrm{H}+_{1}^{2} \mathrm{H} \longrightarrow_{2}^{3} \mathrm{He}+\gamma$ is one of the fusion reactions in the Sun. The mass of $_{1}^{1} \mathrm{H}$ is 1.007825 amu, the mass of $_{1}^{2} \mathrm{H}$ is $2.014102 \mathrm{amu},$ and the mass of $_{2}^{3} \mathrm{He}$ is 3.016029 $\mathrm{amu}$
a. What is the mass deffect of $_{2}^{3}$ He?
b. What energy is released by the process?

Matthew Confer

Numerade Educator

Problem 73

What property of isotopes allows radiotracers to be useful in studying chemical reactions?

Amy Jiang

Numerade Educator

Problem 74

Which unit of radiation dose, rem or rad, is most useful for describing the effect of radiation on living tissue?

Matthew Confer

Numerade Educator

Problem 75

PET scans In PET scans, the radiotracer emits positrons, which travel a few millimeters before interacting with electrons. How can the original radiotracer be detected?

Amy Jiang

Numerade Educator

Problem 76

Figure 24.33 shows a simplified graph of radiation intensity versus distance from the source. Explain this
graph and what itimplies about a method of reducing the effects of radiation exposure.

Matthew Confer

Numerade Educator

Problem 77

Figure 24.34 shows the position of two workers near a radioactive gamma source. The worker at Position A is standing 2.5 $\mathrm{m}$ from the source and receives an exposure of 0.98 mrem $/ \mathrm{s} \cdot \mathrm{m}^{2}$ The worker at Position $\mathrm{B}$ receives an exposure of 0.50 $\mathrm{mrem} / \mathrm{s} \cdot \mathrm{m}^{2} .$ What is the distance of the worker at Position $\mathrm{B}$ from the source?

Amy Jiang

Numerade Educator

Problem 78

A worker stands near a machine that uses a cobalt-60 gamma source to sterilize medical equipment. The worker's dose 2.0 $\mathrm{m}$ from the source is 0.85 $\mathrm{mrem} / \mathrm{s} \cdot \mathrm{m}^{2}$ What is the worker's dose at a distance of 3.5 $\mathrm{m}$ ?

Matthew Confer

Numerade Educator

Problem 79

Safe Exposure The intensity of a radioactive source is 1.15 mrem/s $\cdot \mathrm{m}^{2}$ at a distance of 0.50 $\mathrm{m}$ . What is the minimum distance a person could be from the source to
have a maximum exposure of 0.65 $\mathrm{mrem} / \mathrm{s} \cdot \mathrm{m}^{2} ?$

David Collins

Numerade Educator

Problem 80

Technetium-104 has a half-life of 18.0 min. How much of
a 165.0 g sample remains after 90.0 minutes have passed?

Matthew Confer

Numerade Educator

Problem 81

A bromine-80 nucleus can decay by gamma emission, positron emission, or electron capture. What is the product nucleus in each case?

Amy Jiang

Numerade Educator

Problem 82

The half-life of plutonium-239 is 24,000 y. How much nuclear waste generated today will remain in 1000 years?

Vasu Makani

Numerade Educator

Problem 83

Red blood cells A medical researcher is using a chromium- 51 source to study red blood cells. The gamma-emission intensity at a distance of 1.0 $\mathrm{m}$ is 0.75 mrem $/ \mathrm{s} \cdot \mathrm{m}^{2}$ At what distance would the intensity drop to 0.15 mrem $/$ s.m $^{2} ?$

Madi Sousa

Numerade Educator

Problem 84

The binding energy per nucleon reaches a maximum around what mass number? Explain how this number is related to the fission and fusion processes

Matthew Confer

Numerade Educator

Problem 85

You have an alpha source, a beta source, and a gamma source. Design a plan to use a Geiger counter, paper, and foil to determine the identity of each source.

Amy Jiang

Numerade Educator

Problem 86

What is the half-life of radon-222 if a sample initially contains 150 mg and only 18.7 mg after 11.4 days?

David Collins

Numerade Educator

Problem 87

Sheet metal A company plans to monitor the thickness of sheet metal during production. What would you recommend the company do to determine a safe distance for workers from the gamma source?

Amy Jiang

Numerade Educator

Problem 88

Figure 24.35 shows part of the decay series of a radioisotope. For each segment on the graph, tell whether alpha decay or beta decay occurs, and identify the change in atomic number and mass number.

Matthew Confer

Numerade Educator

Problem 89

Make and Use Graphs Thorium-231 decays to lead-207 by emitting the following particles in successive steps: $\beta, \alpha, \alpha, \beta, \alpha, \alpha, \alpha, \beta, \beta, \alpha .$ Plot each step of the decay series on a graph of mass number versus atomic number. Label each plotted point with the symbol of the radioisotope.

David Collins

Numerade Educator

Problem 90

Apply Chemical treatment is often used to destroy harmful chemicals. For example, bases neutralize acids. Why can’t chemical treatment be applied to destroy the fission products produced in a nuclear reactor?

Matthew Confer

Numerade Educator

Problem 91

Compare A biological concern about working around some radioactive materials is the radioactive dust a person might inhale. Compare the effect of alpha radiation outside the body and inside the body.

Amy Jiang

Numerade Educator

Problem 92

Interpret Small radioactive sources are often used for laboratory experiments. The radioactive substance is enclosed in a metal container with a small window. A gamma source might be covered with a stainless steel window. What would you expect the window of an alpha source to be like? Why?

Matthew Confer

Numerade Educator

Problem 93

Analyze Some radioisotopes used for medical imaging have half-lives as short as several hours. Why is a short half-life beneficial? Why is it a problem?

Amy Jiang

Numerade Educator

Problem 94

Infer The production of electricity at nuclear fission reactor facilities is controversial. Think about the benefits and dangers of this technology. Explain your opinion about whether nuclear reactors should be used

Matthew Confer

Numerade Educator

Problem 95

Use the information in Table 24.8 to calculate the mass defect and binding energy of deuterium $\left(_{1}^{2} \mathrm{H}\right),$ a hydrogen isotope involved in fusion reactions in the Sun.
a. Find the mass of the nucleons.
b. Find the mass defect by subtracting the mass of the nucleons from the mass of the deuterium.
c. Find the binding energy using the conversion 1 amu $=931.49 \mathrm{MeV} .$

Madi Sousa

Numerade Educator

Problem 96

Identify each property as chemical or physical. (Chapter 3)
a. The element mercury has a high density.
b. Solid carbon dioxide sublimes at room temperature.
c. Zinc oxidizes when exposed to air.
d. Sucrose is a white crystalline solid.

Matthew Confer

Numerade Educator

Problem 97

Why does the second period of the periodic table contain eight elements? (Chapter 6)

Amy Jiang

Numerade Educator

Problem 98

Draw each molecule and show the locations of hydrogen bonds between the molecules. (Chapter 8$)$
a. two water molecules
b. two ammonia molecules
c. one water molecule and one ammonia molecule

Matthew Confer

Numerade Educator

Problem 99

What process takes place in each situation? (Chapter 12$)$
a. a solid air-freshener cube getting smaller and smaller
b. dewdrops forming on leaves in the morning
c. steam rising from a hot spring
d. a crust of ice forming on top of a pond

Amy Jiang

Numerade Educator

Problem 100

If the volume of a sample of chlorine gas is 4.5 L at 0.65 atm and 321 K, what volume will the gas occupy at STP? (Chapter 13)

Matthew Confer

Numerade Educator

Problem 101

The temperature of 756 $\mathrm{g}$ of water in a calorimeter increases from $23.2^{\circ} \mathrm{C}$ to $37.6^{\circ} \mathrm{C} .$ How much heat was given off by the reaction in the calorimeter? (Chapter 15$)$

Amy Jiang

Numerade Educator

Problem 102

Explain what a buffer is and why buffers are found in body fluids. (Chapter 18)

Matthew Confer

Numerade Educator

Problem 103

Explain how the structure of benzene can be used to explain its unusually high stability compared to other unsaturated cyclic hydrocarbons. (Chapter 21)

Amy Jiang

Numerade Educator

Problem 104

Marie Curie and Irene Curie Joliot Research and report on the lives of Marie Curie and her daughter,
Irene Curie Joliot. What kind of scientific training did each receive? What was it like to be a female chemist in their time? What discoveries did each make?

Madi Sousa

Numerade Educator

Problem 105

Nuclear Waste Evaluate environmental issues associated with nuclear wastes. Research the Yucca
Mountain nuclear waste disposal plan, the Hanford nuclear site, or a local nuclear facility. Prepare a
poster or multimedia presentation on your findings.

Madi Sousa

Numerade Educator

Problem 106

Radioactive Sources Students in your school might not realize how beneficial radioactive sources can be. Create a poster showing some common, beneficial uses of radioactive sources. Be sure to point out safeguards that are taken to ensure the sources are safe.

Madi Sousa

Numerade Educator

Problem 107

Fluorine-18 is used in medical imaging. If a lab has a sample containing 15 g of fluorine-18, how much
fluorine-18 will remain in the sample after 8.0 h?

Amy Jiang

Numerade Educator

Problem 108

Technetium-99 can be used for diagnostic tests of the heart and lungs. Because of technetium-99’s very
short half-life, medical facilities produce it from molybdenum-99. If the facility has a 25-g sample of
molybdenum-99, how much will it have one week (168 h) later?

Madi Sousa

Numerade Educator

Problem 109

Samarium-153 is used in the production of a drug to treat pain from bone tumors. Radiation released
by the samarium hinders the tumor growth, thereby reducing pain. How much of a 1.0 g sample of
samarium-153 is left after 4 days (96 h)?

Amy Jiang

Numerade Educator