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Chemistry: Atoms First 2e

Exercises

Chemistry: Atoms First 2eExercises
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Table of contents
  1. Preface
  2. 1 Essential Ideas
    1. Introduction
    2. 1.1 Chemistry in Context
    3. 1.2 Phases and Classification of Matter
    4. 1.3 Physical and Chemical Properties
    5. 1.4 Measurements
    6. 1.5 Measurement Uncertainty, Accuracy, and Precision
    7. 1.6 Mathematical Treatment of Measurement Results
    8. Key Terms
    9. Key Equations
    10. Summary
    11. Exercises
  3. 2 Atoms, Molecules, and Ions
    1. Introduction
    2. 2.1 Early Ideas in Atomic Theory
    3. 2.2 Evolution of Atomic Theory
    4. 2.3 Atomic Structure and Symbolism
    5. 2.4 Chemical Formulas
    6. Key Terms
    7. Key Equations
    8. Summary
    9. Exercises
  4. 3 Electronic Structure and Periodic Properties of Elements
    1. Introduction
    2. 3.1 Electromagnetic Energy
    3. 3.2 The Bohr Model
    4. 3.3 Development of Quantum Theory
    5. 3.4 Electronic Structure of Atoms (Electron Configurations)
    6. 3.5 Periodic Variations in Element Properties
    7. 3.6 The Periodic Table
    8. 3.7 Ionic and Molecular Compounds
    9. Key Terms
    10. Key Equations
    11. Summary
    12. Exercises
  5. 4 Chemical Bonding and Molecular Geometry
    1. Introduction
    2. 4.1 Ionic Bonding
    3. 4.2 Covalent Bonding
    4. 4.3 Chemical Nomenclature
    5. 4.4 Lewis Symbols and Structures
    6. 4.5 Formal Charges and Resonance
    7. 4.6 Molecular Structure and Polarity
    8. Key Terms
    9. Key Equations
    10. Summary
    11. Exercises
  6. 5 Advanced Theories of Bonding
    1. Introduction
    2. 5.1 Valence Bond Theory
    3. 5.2 Hybrid Atomic Orbitals
    4. 5.3 Multiple Bonds
    5. 5.4 Molecular Orbital Theory
    6. Key Terms
    7. Key Equations
    8. Summary
    9. Exercises
  7. 6 Composition of Substances and Solutions
    1. Introduction
    2. 6.1 Formula Mass
    3. 6.2 Determining Empirical and Molecular Formulas
    4. 6.3 Molarity
    5. 6.4 Other Units for Solution Concentrations
    6. Key Terms
    7. Key Equations
    8. Summary
    9. Exercises
  8. 7 Stoichiometry of Chemical Reactions
    1. Introduction
    2. 7.1 Writing and Balancing Chemical Equations
    3. 7.2 Classifying Chemical Reactions
    4. 7.3 Reaction Stoichiometry
    5. 7.4 Reaction Yields
    6. 7.5 Quantitative Chemical Analysis
    7. Key Terms
    8. Key Equations
    9. Summary
    10. Exercises
  9. 8 Gases
    1. Introduction
    2. 8.1 Gas Pressure
    3. 8.2 Relating Pressure, Volume, Amount, and Temperature: The Ideal Gas Law
    4. 8.3 Stoichiometry of Gaseous Substances, Mixtures, and Reactions
    5. 8.4 Effusion and Diffusion of Gases
    6. 8.5 The Kinetic-Molecular Theory
    7. 8.6 Non-Ideal Gas Behavior
    8. Key Terms
    9. Key Equations
    10. Summary
    11. Exercises
  10. 9 Thermochemistry
    1. Introduction
    2. 9.1 Energy Basics
    3. 9.2 Calorimetry
    4. 9.3 Enthalpy
    5. 9.4 Strengths of Ionic and Covalent Bonds
    6. Key Terms
    7. Key Equations
    8. Summary
    9. Exercises
  11. 10 Liquids and Solids
    1. Introduction
    2. 10.1 Intermolecular Forces
    3. 10.2 Properties of Liquids
    4. 10.3 Phase Transitions
    5. 10.4 Phase Diagrams
    6. 10.5 The Solid State of Matter
    7. 10.6 Lattice Structures in Crystalline Solids
    8. Key Terms
    9. Key Equations
    10. Summary
    11. Exercises
  12. 11 Solutions and Colloids
    1. Introduction
    2. 11.1 The Dissolution Process
    3. 11.2 Electrolytes
    4. 11.3 Solubility
    5. 11.4 Colligative Properties
    6. 11.5 Colloids
    7. Key Terms
    8. Key Equations
    9. Summary
    10. Exercises
  13. 12 Thermodynamics
    1. Introduction
    2. 12.1 Spontaneity
    3. 12.2 Entropy
    4. 12.3 The Second and Third Laws of Thermodynamics
    5. 12.4 Free Energy
    6. Key Terms
    7. Key Equations
    8. Summary
    9. Exercises
  14. 13 Fundamental Equilibrium Concepts
    1. Introduction
    2. 13.1 Chemical Equilibria
    3. 13.2 Equilibrium Constants
    4. 13.3 Shifting Equilibria: Le Châtelier’s Principle
    5. 13.4 Equilibrium Calculations
    6. Key Terms
    7. Key Equations
    8. Summary
    9. Exercises
  15. 14 Acid-Base Equilibria
    1. Introduction
    2. 14.1 Brønsted-Lowry Acids and Bases
    3. 14.2 pH and pOH
    4. 14.3 Relative Strengths of Acids and Bases
    5. 14.4 Hydrolysis of Salts
    6. 14.5 Polyprotic Acids
    7. 14.6 Buffers
    8. 14.7 Acid-Base Titrations
    9. Key Terms
    10. Key Equations
    11. Summary
    12. Exercises
  16. 15 Equilibria of Other Reaction Classes
    1. Introduction
    2. 15.1 Precipitation and Dissolution
    3. 15.2 Lewis Acids and Bases
    4. 15.3 Coupled Equilibria
    5. Key Terms
    6. Key Equations
    7. Summary
    8. Exercises
  17. 16 Electrochemistry
    1. Introduction
    2. 16.1 Review of Redox Chemistry
    3. 16.2 Galvanic Cells
    4. 16.3 Electrode and Cell Potentials
    5. 16.4 Potential, Free Energy, and Equilibrium
    6. 16.5 Batteries and Fuel Cells
    7. 16.6 Corrosion
    8. 16.7 Electrolysis
    9. Key Terms
    10. Key Equations
    11. Summary
    12. Exercises
  18. 17 Kinetics
    1. Introduction
    2. 17.1 Chemical Reaction Rates
    3. 17.2 Factors Affecting Reaction Rates
    4. 17.3 Rate Laws
    5. 17.4 Integrated Rate Laws
    6. 17.5 Collision Theory
    7. 17.6 Reaction Mechanisms
    8. 17.7 Catalysis
    9. Key Terms
    10. Key Equations
    11. Summary
    12. Exercises
  19. 18 Representative Metals, Metalloids, and Nonmetals
    1. Introduction
    2. 18.1 Periodicity
    3. 18.2 Occurrence and Preparation of the Representative Metals
    4. 18.3 Structure and General Properties of the Metalloids
    5. 18.4 Structure and General Properties of the Nonmetals
    6. 18.5 Occurrence, Preparation, and Compounds of Hydrogen
    7. 18.6 Occurrence, Preparation, and Properties of Carbonates
    8. 18.7 Occurrence, Preparation, and Properties of Nitrogen
    9. 18.8 Occurrence, Preparation, and Properties of Phosphorus
    10. 18.9 Occurrence, Preparation, and Compounds of Oxygen
    11. 18.10 Occurrence, Preparation, and Properties of Sulfur
    12. 18.11 Occurrence, Preparation, and Properties of Halogens
    13. 18.12 Occurrence, Preparation, and Properties of the Noble Gases
    14. Key Terms
    15. Summary
    16. Exercises
  20. 19 Transition Metals and Coordination Chemistry
    1. Introduction
    2. 19.1 Occurrence, Preparation, and Properties of Transition Metals and Their Compounds
    3. 19.2 Coordination Chemistry of Transition Metals
    4. 19.3 Spectroscopic and Magnetic Properties of Coordination Compounds
    5. Key Terms
    6. Summary
    7. Exercises
  21. 20 Nuclear Chemistry
    1. Introduction
    2. 20.1 Nuclear Structure and Stability
    3. 20.2 Nuclear Equations
    4. 20.3 Radioactive Decay
    5. 20.4 Transmutation and Nuclear Energy
    6. 20.5 Uses of Radioisotopes
    7. 20.6 Biological Effects of Radiation
    8. Key Terms
    9. Key Equations
    10. Summary
    11. Exercises
  22. 21 Organic Chemistry
    1. Introduction
    2. 21.1 Hydrocarbons
    3. 21.2 Alcohols and Ethers
    4. 21.3 Aldehydes, Ketones, Carboxylic Acids, and Esters
    5. 21.4 Amines and Amides
    6. Key Terms
    7. Summary
    8. Exercises
  23. A | The Periodic Table
  24. B | Essential Mathematics
  25. C | Units and Conversion Factors
  26. D | Fundamental Physical Constants
  27. E | Water Properties
  28. F | Composition of Commercial Acids and Bases
  29. G | Standard Thermodynamic Properties for Selected Substances
  30. H | Ionization Constants of Weak Acids
  31. I | Ionization Constants of Weak Bases
  32. J | Solubility Products
  33. K | Formation Constants for Complex Ions
  34. L | Standard Electrode (Half-Cell) Potentials
  35. M | Half-Lives for Several Radioactive Isotopes
  36. Answer Key
    1. Chapter 1
    2. Chapter 2
    3. Chapter 3
    4. Chapter 4
    5. Chapter 5
    6. Chapter 6
    7. Chapter 7
    8. Chapter 8
    9. Chapter 9
    10. Chapter 10
    11. Chapter 11
    12. Chapter 12
    13. Chapter 13
    14. Chapter 14
    15. Chapter 15
    16. Chapter 16
    17. Chapter 17
    18. Chapter 18
    19. Chapter 19
    20. Chapter 20
    21. Chapter 21
  37. Index

20.1 Nuclear Structure and Stability

1.

Write the following isotopes in hyphenated form (e.g., “carbon-14”)

(a) 1124Na1124Na

(b) 1329Al1329Al

(c) 3673Kr3673Kr

(d) 77194Ir77194Ir

2.

Write the following isotopes in nuclide notation (e.g., "614C")"614C")

(a) oxygen-14

(b) copper-70

(c) tantalum-175

(d) francium-217

3.

For the following isotopes that have missing information, fill in the missing information to complete the notation

(a) 1434X1434X

(b) X36PX36P

(c) X57MnX57Mn

(d) 56121X56121X

4.

For each of the isotopes in Exercise 20.1, determine the numbers of protons, neutrons, and electrons in a neutral atom of the isotope.

5.

Write the nuclide notation, including charge if applicable, for atoms with the following characteristics:

(a) 25 protons, 20 neutrons, 24 electrons

(b) 45 protons, 24 neutrons, 43 electrons

(c) 53 protons, 89 neutrons, 54 electrons

(d) 97 protons, 146 neutrons, 97 electrons

6.

Calculate the density of the 1224Mg1224Mg nucleus in g/mL, assuming that it has the typical nuclear diameter of 1 ×× 10–13 cm and is spherical in shape.

7.

What are the two principal differences between nuclear reactions and ordinary chemical changes?

8.

The mass of the atom 1123Na1123Na is 22.9898 amu.

(a) Calculate its binding energy per atom in millions of electron volts.

(b) Calculate its binding energy per nucleon.

9.

Which of the following nuclei lie within the band of stability shown in Figure 20.2?

(a) chlorine-37

(b) calcium-40

(c) 204Bi

(d) 56Fe

(e) 206Pb

(f) 211Pb

(g) 222Rn

(h) carbon-14

10.

Which of the following nuclei lie within the band of stability shown in Figure 20.2?

(a) argon-40

(b) oxygen-16

(c) 122Ba

(d) 58Ni

(e) 205Tl

(f) 210Tl

(g) 226Ra

(h) magnesium-24

20.2 Nuclear Equations

11.

Write a brief description or definition of each of the following:

(a) nucleon

(b) α particle

(c) β particle

(d) positron

(e) γ ray

(f) nuclide

(g) mass number

(h) atomic number

12.

Which of the various particles (α particles, β particles, and so on) that may be produced in a nuclear reaction are actually nuclei?

13.

Complete each of the following equations by adding the missing species:

(a) 1327Al+24He⟶?+01n1327Al+24He⟶?+01n

(b) 94239Pu+?⟶ 96 242Cm+ 01n94239Pu+?⟶ 96 242Cm+ 01n

(c) 714N+24He⟶?+11H714N+24He⟶?+11H

(d) 92235U⟶?+55135Cs+401n92235U⟶?+55135Cs+401n

14.

Complete each of the following equations:

(a) 37Li+?⟶224He37Li+?⟶224He

(b) 614C⟶714N+?614C⟶714N+?

(c) 1327Al+24He⟶?+01n1327Al+24He⟶?+01n

(d) 96250Cm⟶?+3898Sr+401n96250Cm⟶?+3898Sr+401n

15.

Write a balanced equation for each of the following nuclear reactions:

(a) the production of 17O from 14N by α particle bombardment

(b) the production of 14C from 14N by neutron bombardment

(c) the production of 233Th from 232Th by neutron bombardment

(d) the production of 239U from 238U by 12H12H bombardment

16.

Technetium-99 is prepared from 98Mo. Molybdenum-98 combines with a neutron to give molybdenum-99, an unstable isotope that emits a β particle to yield an excited form of technetium-99, represented as 99Tc*. This excited nucleus relaxes to the ground state, represented as 99Tc, by emitting a γ ray. The ground state of 99Tc then emits a β particle. Write the equations for each of these nuclear reactions.

17.

The mass of the atom 919F919F is 18.99840 amu.

(a) Calculate its binding energy per atom in millions of electron volts.

(b) Calculate its binding energy per nucleon.

18.

For the reaction 614C⟶714N+?,614C⟶714N+?, if 100.0 g of carbon reacts, what volume of nitrogen gas (N2) is produced at 273K and 1 atm?

20.3 Radioactive Decay

19.

What are the types of radiation emitted by the nuclei of radioactive elements?

20.

What changes occur to the atomic number and mass of a nucleus during each of the following decay scenarios?

(a) an α particle is emitted

(b) a β particle is emitted

(c) γ radiation is emitted

(d) a positron is emitted

(e) an electron is captured

21.

What is the change in the nucleus that results from the following decay scenarios?

(a) emission of a β particle

(b) emission of a β+ particle

(c) capture of an electron

22.

Many nuclides with atomic numbers greater than 83 decay by processes such as electron emission. Explain the observation that the emissions from these unstable nuclides also normally include α particles.

23.

Why is electron capture accompanied by the emission of an X-ray?

24.

Explain, in terms of Figure 20.2, how unstable heavy nuclides (atomic number > 83) may decompose to form nuclides of greater stability (a) if they are below the band of stability and (b) if they are above the band of stability.

25.

Which of the following nuclei is most likely to decay by positron emission? Explain your choice.

(a) chromium-53

(b) manganese-51

(c) iron-59

26.

The following nuclei do not lie in the band of stability. How would they be expected to decay? Explain your answer.

(a) 1534P 1534P

(b) 92239U 92239U

(c) 2038Ca 2038Ca

(d) 13H 13H

(e) 94245Pu 94245Pu

27.

The following nuclei do not lie in the band of stability. How would they be expected to decay?

(a) 1528P 1528P

(b) 92235U 92235U

(c) 2037Ca 2037Ca

(d) 39L i 39L i

(e) 96245Cm 96245Cm

28.

Predict by what mode(s) of spontaneous radioactive decay each of the following unstable isotopes might proceed:

(a) 26H e 26H e

(b) 3060Zn 3060Zn

(c) 91235Pa 91235Pa

(d) 94241Np 94241Np

(e) 18F

(f) 129Ba

(g) 237Pu

29.

Write a nuclear reaction for each step in the formation of 84218Po 84218Po from 92238U , 92238U , which proceeds by a series of decay reactions involving the step-wise emission of α, β, β, α, α, α particles, in that order.

30.

Write a nuclear reaction for each step in the formation of 82208Pb 82208Pb from 90228T h, 90228T h, which proceeds by a series of decay reactions involving the step-wise emission of α, α, α, α, β, β, α particles, in that order.

31.

Define the term half-life and illustrate it with an example.

32.

A 1.00 ×× 10–6-g sample of nobelium, 102254No , 102254No , has a half-life of 55 seconds after it is formed. What is the percentage of 102254No 102254No remaining at the following times?

(a) 5.0 min after it forms

(b) 1.0 h after it forms

33.

239Pu is a nuclear waste byproduct with a half-life of 24,000 y. What fraction of the 239Pu present today will be present in 1000 y?

34.

The isotope 208Tl undergoes β decay with a half-life of 3.1 min.

(a) What isotope is produced by the decay?

(b) How long will it take for 99.0% of a sample of pure 208Tl to decay?

(c) What percentage of a sample of pure 208Tl remains un-decayed after 1.0 h?

35.

If 1.000 g of 88226Ra 88226Ra produces 0.0001 mL of the gas 86222Rn 86222Rn at STP (standard temperature and pressure) in 24 h, what is the half-life of 226Ra in years?

36.

The isotope 3890Sr 3890Sr is one of the extremely hazardous species in the residues from nuclear power generation. The strontium in a 0.500-g sample diminishes to 0.393 g in 10.0 y. Calculate the half-life.

37.

Technetium-99 is often used for assessing heart, liver, and lung damage because certain technetium compounds are absorbed by damaged tissues. It has a half-life of 6.0 h. Calculate the rate constant for the decay of 4399Tc . 4399Tc .

38.

What is the age of mummified primate skin that contains 8.25% of the original quantity of 14C?

39.

A sample of rock was found to contain 8.23 mg of rubidium-87 and 0.47 mg of strontium-87.

(a) Calculate the age of the rock if the half-life of the decay of rubidium by β emission is 4.7 ×× 1010 y.

(b) If some 3887Sr 3887Sr was initially present in the rock, would the rock be younger, older, or the same age as the age calculated in (a)? Explain your answer.

40.

A laboratory investigation shows that a sample of uranium ore contains 5.37 mg of 92238U 92238U and 2.52 mg of 82206Pb . 82206Pb . Calculate the age of the ore. The half-life of 92238U 92238U is 4.5 ×× 109 yr.

41.

Plutonium was detected in trace amounts in natural uranium deposits by Glenn Seaborg and his associates in 1941. They proposed that the source of this 239Pu was the capture of neutrons by 238U nuclei. Why is this plutonium not likely to have been trapped at the time the solar system formed 4.7 ×× 109 years ago?

42.

A 47Be 47Be atom (mass = 7.0169 amu) decays into a 37L i 37L i atom (mass = 7.0160 amu) by electron capture. How much energy (in millions of electron volts, MeV) is produced by this reaction?

43.

A 58B 58B atom (mass = 8.0246 amu) decays into a 48Be 48Be atom (mass = 8.0053 amu) by loss of a β+ particle (mass = 0.00055 amu) or by electron capture. How much energy (in millions of electron volts) is produced by this reaction?

44.

Isotopes such as 26Al (half-life: 7.2 ×× 105 years) are believed to have been present in our solar system as it formed, but have since decayed and are now called extinct nuclides.

(a) 26Al decays by β+ emission or electron capture. Write the equations for these two nuclear transformations.

(b) The earth was formed about 4.7 ×× 109 (4.7 billion) years ago. How old was the earth when 99.999999% of the 26Al originally present had decayed?

45.

Write a balanced equation for each of the following nuclear reactions:

(a) bismuth-212 decays into polonium-212

(b) beryllium-8 and a positron are produced by the decay of an unstable nucleus

(c) neptunium-239 forms from the reaction of uranium-238 with a neutron and then spontaneously converts into plutonium-239

(d) strontium-90 decays into yttrium-90

46.

Write a balanced equation for each of the following nuclear reactions:

(a) mercury-180 decays into platinum-176

(b) zirconium-90 and an electron are produced by the decay of an unstable nucleus

(c) thorium-232 decays and produces an alpha particle and a radium-228 nucleus, which decays into actinium-228 by beta decay

(d) neon-19 decays into fluorine-19

20.4 Transmutation and Nuclear Energy

47.

Write the balanced nuclear equation for the production of the following transuranium elements:

(a) berkelium-244, made by the reaction of Am-241 and He-4

(b) fermium-254, made by the reaction of Pu-239 with a large number of neutrons

(c) lawrencium-257, made by the reaction of Cf-250 and B-11

(d) dubnium-260, made by the reaction of Cf-249 and N-15

48.

How does nuclear fission differ from nuclear fusion? Why are both of these processes exothermic?

49.

Both fusion and fission are nuclear reactions. Why is a very high temperature required for fusion, but not for fission?

50.

Cite the conditions necessary for a nuclear chain reaction to take place. Explain how it can be controlled to produce energy, but not produce an explosion.

51.

Describe the components of a nuclear reactor.

52.

In usual practice, both a moderator and control rods are necessary to operate a nuclear chain reaction safely for the purpose of energy production. Cite the function of each and explain why both are necessary.

53.

Describe how the potential energy of uranium is converted into electrical energy in a nuclear power plant.

54.

The mass of a hydrogen atom (11H)(11H) is 1.007825 amu; that of a tritium atom (13H)(13H) is 3.01605 amu; and that of an α particle is 4.00150 amu. How much energy in kilojoules per mole of 24He24He produced is released by the following fusion reaction: 11H+13H⟶24He.11H+13H⟶24He.

20.5 Uses of Radioisotopes

55.

How can a radioactive nuclide be used to show that the equilibrium:
 AgCl(s)⇌Ag+(aq)+Cl−(aq)AgCl(s)⇌Ag+(aq)+Cl−(aq)
 is a dynamic equilibrium?

56.

Technetium-99m has a half-life of 6.01 hours. If a patient injected with technetium-99m is safe to leave the hospital once 75% of the dose has decayed, when is the patient allowed to leave?

57.

Iodine that enters the body is stored in the thyroid gland from which it is released to control growth and metabolism. The thyroid can be imaged if iodine-131 is injected into the body. In larger doses, I-133 is also used as a means of treating cancer of the thyroid. I-131 has a half-life of 8.70 days and decays by β− emission.

(a) Write an equation for the decay.

(b) How long will it take for 95.0% of a dose of I-131 to decay?

20.6 Biological Effects of Radiation

58.

If a hospital were storing radioisotopes, what is the minimum containment needed to protect against:

(a) cobalt-60 (a strong γ emitter used for irradiation)

(b) molybdenum-99 (a beta emitter used to produce technetium-99 for imaging)

59.

Based on what is known about Radon-222’s primary decay method, why is inhalation so dangerous?

60.

Given specimens uranium-232 (t1/2 = 68.9 y) and uranium-233 (t1/2 = 159,200 y) of equal mass, which one would have greater activity and why?

61.

A scientist is studying a 2.234 g sample of thorium-229 (t1/2 = 7340 y) in a laboratory.

(a) What is its activity in Bq?

(b) What is its activity in Ci?

62.

Given specimens neon-24 (t1/2 = 3.38 min) and bismuth-211 (t1/2 = 2.14 min) of equal mass, which one would have greater activity and why?

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