Final Review Questions

Kinetics

____ 1. Which of the five factors listed does not affect the rate of a homogeneous reaction?

a.	the presence of catalysts
b.	the concentrations of reactants
c.	the temperature of the reaction system
d.	the surface area of the reactants
e.	the properties of the reactants and the products

____ 2. Which statement describes a correct approach to determining the rate law for a reaction?

a.	Balance the chemical equation and use the coefficients of the reactants as exponents for the concentrations of reactants.
b.	Balance the chemical equation and use the coefficients of the reactants as factors for the concentrations.
c.	Balance the chemical equation and use the reciprocals of the coefficients of the reactants as factors for the concentrations.
d.	Perform experiments in which the initial rate of the reaction is measured using varying amounts of each reactant.
e.	Perform experiments in which the concentration of each reactant is measured at specific time intervals.

____ 3. The rate constant for the first order decomposition of SO₂Cl₂ at a very high temperature is 1.37 ´ 10^-3 min^-1. If the initial concentration is 0.500 M, predict the concentration after five hours (300 min).

a.	0.500 M
b.	6.85 ´ 10^-4 M
c.	0.331 M
d.	1.33 M
e.	0.754 M

____ 4. When the structure of only one atom, molecule or ion is rearranged to produce a new species, the process is called a(an)

a.	activated complex
b.	activation energy
c.	bimolecular reaction
d.	steric factor
e.	unimolecular reaction

____ 5. When two particles must collide to produce a new species, the process is called a(an)

a.	activated complex
b.	activation energy
c.	bimolecular reaction
d.	steric factor
e.	unimolecular reaction

____ 6. Which of the following factors increases the rate of a chemical reaction by increasing the number of molecules with enough energy to overcome the activation energy barrier?

a.	increasing the temperature
b.	increasing the concentration of reactants
c.	increasing the concentration of products
d.	adding a catalyst
e.	increasing the surface area of a phase interface

____ 8. The solid catalysts used in many industrial processes where the reactants are liquids or gases are referred to as

a.	enzymes.
b.	heterogeneous catalysts.
c.	homogeneous catalysts.
d.	silicon catalysts.
e.	zeolites.

74. In your own words distinguish between the average rate of a reaction over a certain time interval and the instantaneous reaction rate at a particular time.

75. Sketch a reaction diagram for the endothermic conversion of A ® B, where the activation energy is 50 kJ/mol, and the DE, which = DH, is 25 kJ/mol. Label the reactant as A, the product as B, the activated complex or transition state as AC, the activation energy as E_a, and the reaction energy as DE.

76. Consider the reaction with the mechanism shown:

2NO	®	N₂O₂					slow
N₂O₂	+	H₂	®	N₂O	+	H₂O	fast
N₂O	+	H₂	®	N₂	+	H₂O	fast

a. Write the overall reaction represented by this mechanism.

b. What are the intermediates in this reaction, if any?

c. What are the catalysts in this reaction, if any?

d. Write the rate law for this reaction. Explain your answer.

Equilibrium

____ 9. Consider the reaction

COCl₂(g) <===> CO(g) + Cl₂(g)

At equilibrium, [CO] = 4.14 ´ 10^-6 M; [Cl₂] = 4.14 ´ 10^-6 M; and [COCl₂] = 0.0627 M. Calculate the value of the equilibrium constant.

a.	1.32 ´ 10^-4
b.	1.51 ´ 10⁴
c.	2.73 ´ 10^-10
d.	3.66 ´ 10⁹
e.	6.60 ´ 10^-5

____ 10. Consider the reaction system:

2N₂(g) + O₂(g) ¬¾® 2N₂O(g)

K_c = 1.5 ´ 10^-30

At equilibrium, the concentration of N₂ was measured as 0.048 M and the concentration of O₂ as 0.093 M. What is the concentration of N₂O in this system?

a.	8.2 ´ 10^-17
b.	1.8 ´ 10^-17
c.	4.7 ´ 10^-27
d.	3.4 ´ 10^-28
e.	3.2 ´ 10^-34

____ 11. Consider the equilibrium system

C(s) + CO₂(g) <====> 2CO(g)

If CO₂ is added, the equilibrium will ____, and if CO is added the equilibrium will ____.

a.	shift forward; shift reverse
b.	shift forward; shift forward
c.	shift reverse; shift reverse
d.	be unchanged; shift forward
e.	neither can be predicted

____ 12. Consider the equilibrium system

C(s) + CO₂(g) <====> 2CO(g)

If the pressure on the system is increased the equilibrium will _____, because _____.

a.	shift forward; higher pressure favors fewer moles of gas
b.	shift forward; higher pressure favors more moles of gas
c.	shift reverse; higher pressure favors fewer moles of gas
d.	shift reverse; higher pressure favors more moles of gas
e.	be unchanged; of the presence of the solid C

____ 13. Considering only the probability factor in the gaseous reaction 2A + B <===> C, the ____ side is favored because ____.

a.	product; there are more possible arrangements of molecules on the reactant side
b.	product; there are more possible arrangements of molecules on the product side
c.	reactant; there are more possible arrangements of molecules on the reactant side
d.	reactant; there are more possible arrangements of molecules on the product side
e.	More information is needed to determine which side is favored.

____ 14. Which statement concerning product-favored reactions is not correct?

a.	The value of the equilibrium constant is greater than 1.
b.	An endothermic reaction is product-favored.
c.	If the entropy of the products is greater than the entropy of the reactants, the reaction is product-favored.
d.	If a reaction is product-favored at high temperature, the entropy of the products is probably greater than the entropy of the reactants.
e.	If a reaction is product-favored at low temperature, the enthalpy of the products is probably less than the enthalpy of the reactants.

77. Consider the statement, "At equilibrium, no chemistry is occurring because the reaction has been completed."

a. Is this statement true or false?

b. Explain your answer in detail. Be sure to consider the situation both from a macroscopic viewpoint and a nanoscale viewpoint.

78. The interhalogen compound bromine chloride is formed by the reaction of bromine vapor and chlorine gas. The compound is a gas at the temperature of this reaction.

a. Write the balanced equation for the reaction. Also write the K_c expression.

b. K_c = 6.87 and a 2.00 L flask initially contains chlorine at a concentration of 0.51 M and bromine at a concentration of 0.34 M. When equilibrium is reached, the concentration of bromine chloride is 0.46 M. Calculate the equilibrium concentrations of bromine and chlorine.

c. Consider the reaction system in part b. In what direction will the reaction shift if the volume of the container is increased to 4.0 L? _____ Explain your answer.

d. Consider the reaction system in part b. In what direction will the reaction shift if bromine chloride is added? _____ Explain your answer.

e. Consider the reaction system in part b. In what direction will the reaction shift if a catalyst is added? _____ Explain your answer.

Solutions

____ 15. A solution is a

a.	homogeneous mixture of two or more substances.
b.	heterogeneous mixture of at least three substances.
c.	mixture of two or more substances in which the heavier particles can "settle out."
d.	homogeneous mixture of an element with a compound.
e.	homogenous mixture containing two or more compounds.

____ 16. If a liquid is miscible with water, some portion of the molecule is _____, which means that it is _____.

a.	polar; hydrophobic
b.	polar; hydrophilic
c.	nonpolar; hydrophobic
d.	nonpolar; hydrophilic
e.	bipolar; insoluble

____ 17. When a solution is saturated the concentration of the solute is _____ the solubility, and _____ solute will dissolve.

a.	greater than; more
b.	greater than; no more
c.	equal to; no more
d.	less than; no more
e.	less than; more

____ 19. The unit M means _____, which is defined as _____.

a.	molality; moles solute/mole solvent
b.	molality; moles solute/kg solvent
c.	molarity; mass solute/mass solution
d.	molarity; moles solute/mole solvent
e.	molarity; moles solute/liter solution

____ 20. What is the molarity of technical grade concentrated sulfuric acid, H₂SO₄, which is labeled 95% and has a density of 1.84 g/mL?

a.	0.969 M
b.	1.84 M
c.	17.8 M
d.	51.6 M
e.	98.0 M

____ 21. An aqueous solution at 27°C contains 4.2 g of a protein in a 200. mL sample. The osmotic pressure is 0.0237 atm. What is the molar mass of the protein?

a.	2.2 ´ 10⁴ g/mol
b.	870 g/mol
c.	2.0 ´ 10³ g/mol
d.	79 g/mol
e.	22 g/mol

____ 22. In living systems, a solution that is ____ has a lower solute concentration than the surrounding cells and therefore causes water to flow _____ the cells by osmosis.

a.	hypertonic; into
b.	hypotonic; into
c.	isotonic; into
d.	hypertonic; out of
e.	hypotonic; out of

79. Explain the arrangement of these compounds in order of increasing solubility in water:

CH₃(CH₂)₅CH₃ < CH₃(CH₂)₅OH < HO(CH₂)₅OH

80. The solubility of sodium acetate, NaC₂H₃O₂, is 75 g/100 mL. Determine whether a solution containing 365 g NaC₂H₃O₂ in 475 mL water is unsaturated, saturated, or supersaturated. Show a calculation to support your answer.

Acids and Bases

____ 25. The reaction between ethylamine, an organic base, and hydrochloric acid is written as _____. The formula for ethylamine is CH₃CH₂NH₂.

a.	CH₃CH₂NH₂ + HCl <===> CH₄CH₂NH₂⁺Cl^-
b.	CH₃CH₂NH₂ + HCl <===> CH₃CH₃NH₂⁺Cl^-
c.	CH₃CH₂NH₂ + 2HCl <===> CH₃CH₂NH₄²⁺Cl₂^-
d.	CH₃CH₂NH₂ + HCl <===> CH₃CH₂NH₃⁺Cl^-
e.	CH₃CH₂NH₂ + HCl <===> CH₃CH₂NH^-H₂Cl⁺

____ 26. Calculate the [H⁺] and [OH^-] in a 1.2 M KOH solution, a strong base. [H⁺] = _____, and [OH^-] = _____.

a.	1.2 M; 1.2 M
b.	1.2 M; 8.3 ´ 10^-15 M
c.	8.3 ´ 10^-15 M; 1.2 M
d.	8.3 ´ 10^-15 M; 1.0 ´ 10^-14 M
e.	1.0 ´ 10^-7 M; 1.0 ´ 10^-7 M

____ 27. Calculate the [H⁺] and [OH^-] in a 1.2 M HClO₄ solution, a strong acid. [H⁺] = _____, and [OH^-] = _____.

a.	1.2 M; 1.2 M
b.	1.2 M; 8.3 ´ 10^-15 M
c.	8.3 ´ 10^-15 M; 1.2 M
d.	8.3 ´ 10^-15 M; 1.0 ´ 10^-14 M
e.	1.0 ´ 10^-7 M; 1.0 ´ 10^-7 M

____ 28. Calculate the pH of a solution where [OH^-] = 4.6 ´ 10^-4. Is this solution acidic or basic?

a.	4.60; basic
b.	10.66; basic
c.	10.66; acidic
d.	3.34; basic
e.	3.34; acidic

____ 29. Which statement about a 0.50 M sample of the weak acid, HNO₂, Ka = 4.5 ´ 10^-4, is not correct?

a.	[H⁺] = 0.50 M.
b.	The acid is only slightly ionized.
c.	The sample contains mostly un-ionized HNO₂ molecules.
d.	The pH is slightly less than 2.0.
e.	[H⁺] > [OH^-].

____ 30. For the basic compound strychnine, the value of Kb is 1.8 ´ 10^-6. What is the pH of a 0.085 M solution of this poison?

a.	3.41
b.	6.81
c.	7.18
d.	10.59
e.	11.66

____ 31. Acid-base chemistry causes some baked goods to "rise" by producing

a.	carbon dioxide when an acid reacts with sodium bicarbonate in baking soda.
b.	hydrogen gas from trace metals that react with acids in the batter.
c.	steam from the water formed in neutralization.
d.	carbon dioxide and ethanol as fermentation products.
e.	sulfur dioxide from sulfite-containing foods.

____ 32. The association between a Lewis acid and a Lewis base is called a(an) _____ bond.

a.	acidic
b.	coordinate covalent
c.	hydrogen
d.	ionic
e.	metallic

82. a. Write the reaction for the ionization of the weak acid HA in water.

b. Write the reaction for the ionization of the conjugate base of the weak acid HA in water.

c. Using equilibrium constant expressions for the reaction of HA and its conjugate base A^- with water, show why the product of Ka and Kb is always equal to 10^-14 at 25°C.

More Aqueous Equilibria

____ 33. Which pair of compounds could be used to make a buffer solution?

a.	NaCl/HCl
b.	(NH₄)₂SO₄/H₂SO₄
c.	NaCH₃COO/CH₃COOH
d.	K₃PO₄/KH₂PO₄
e.	KOH/KBr

____ 34. Which formula represents the Henderson-Hasselbalch equation for the generic acid HA?

a.
b.
c.
d.
e.

____ 36. Write the Ksp expression for silver phosphate, Ag₃PO₄.

a.	[Ag⁺]³[PO₄^3-]
b.
c.	3x[Ag⁺][PO₄^3-]
d.	3x[Ag⁺]³ + [PO₄^3-]
e.	[H⁺][OH^-]

____ 37. Calculate the molar solubility of silver chloride, AgCl, in a solution in which [Cl^-] = 0.045 M. Ksp = 1.8 ´ 10^-10 for silver chloride.

a.	1.3 ´ 10-⁵
b.	2.5 ´ 10^-8
c.	4.0 ´ 10^-9
d.	1.8 ´ 10^-10
e.	8.1 ´ 10^-12

____ 38. In which solution would calcium phosphate have the greatest solubility?

a.	0.1 M phosphoric acid
b.	0.1 M sodium phosphate
c.	saturated calcium hydroxide
d.	0.1 M calcium nitrate
e.	distilled water

____ 39. Which mixture would dissolve the largest amount of barium sulfate?

a.	0.1 M HCl
b.	0.1 M Ba(NO₃)₂
c.	0.1 M Mg(OH)₂
d.	0.1 M Na₂SO₄
e.	0.1 M Al₂(SO₄)₃

83. How will the addition of 0.1 M NH₃ to a saturated solution of CuCO₃ affect the solubility of the CuCO₃? Show a calculation to support your answer.

Ksp for copper(II) carbonate = 2.5 ´ 10^-10

Kf for copper(II) tetraammine = 1.1 ´ 10¹³

84. Consider two saturated solutions, one of CuCO₃ and one of Cu₃(PO₄)₂. How will each solution be affected by the addition of 0.1 M NH₃? Show a calculation to support your answer.

Ksp for copper(II) carbonate = 2.5 ´ 10^-10

Ksp for copper(II) phosphate = 1.4 ´ 10^-37

Kf for copper(II) tetraammine = 1.1 ´ 10¹³

Kb for ammonia = 1.8 ´ 10^-5

Thermodynamics

____ 40. If a coin is tossed five times, which of the arrangements shown is least likely?

a.	THTHT
b.	HHTHT
c.	THHTT
d.	TTTHT
e.	HTTHT

____ 41. Which statement about entropy is not correct?

a.	The entropy of a particular sample is greater in the gaseous state than in the solid state.
b.	In considering a series of similar, but increasingly larger molecules all in the same state, the largest molecule will have greatest entropy.
c.	Because of the larger charges, the entropy of CaO is less than the entropy of KF.
d.	Entropy decreases when ethanol, C₂H₅OH, dissolves in water.
e.	A bottle of carbonated water has lower entropy than the same masses of carbon dioxide gas and distilled water.

____ 42. Which process illustrates a decrease in entropy?

a.	baking a cake from scratch
b.	making tossed salad
c.	producing aluminum foil from bauxite ore
d.	shuffling a deck of cards
e.	spreading grass seed on a lawn

____ 43. Calculate the value of DS° for the reaction shown:

C₃H₈(g) + 5O₂(g) ® 4H₂O(g) + 3CO₂(g)

At 25°C the values of entropy in J/mol-K are propane, 270.2; oxygen, 205.15; water, 188.74; carbon dioxide, 213.80.

a.	-100.41 J/K
b.	-72.81 J/K
c.	72.81 J/K
d.	100.41 J/K
e.	921.01 J/K

____ 44. Calculate the value of DS° for the reaction shown:

N₂(g) + 3H₂(g) ® 2NH₃(g)

At 25°C the values of entropy in J/mol-K are nitrogen, 191.61: hydrogen, 130.68; and ammonia, 192.77.

a.	-969.19 J/K
b.	-393.20 J/K
c.	-390.88 J/K
d.	-198.11 J/K
e.	-129.52 J/K

____ 45. According to the second law of thermodynamics,

a.	any process in which entropy increases will be product-favored.
b.	any process which is endothermic will be product-favored.
c.	only processes in which the entropy of the universe is increasing will be product-favored.
d.	heat will always be transferred from a warmer object to a cooler object.
e.	the total amount of matter in the universe remains constant.

____ 46. Which statement regarding the Gibbs free energy of a system is not correct?

a.	It is defined as -TDS_universe.
b.	In a product-favored reaction, its value is less than zero.
c.	Its value is a function of DS_surroundings and DS_system.
d.	Its value is zero when DH_system = DS_system.
e.	The previous four statements are all correct.

____ 47. The value of the equilibrium constant for a reaction is 2.65 ´ 10^-6 at 35°C. Calculate the value of .

a.	1.62 kJ
b.	3.74 kJ
c.	14.2 kJ
d.	29.1 kJ
e.	32.9 kJ

____ 48. Use the data given to calculate the value of K for the reaction at 5°C.

AgCl(s) ® Ag⁺(aq) + Cl^-(aq)

a.	9.76 ´ 10^-1
b.	7.68 ´ 10^-7
c.	1.76 ´ 10^-10
d.	2.61 ´ 10^-11
e.	5.10 ´ 10^-13

____ 49. Identify the statement which best explains the term "coupled reaction."

a.	A reactant-favored reaction consumes the products from a product-favored reaction.
b.	The heat released from an exothermic reaction is used in a related endothermic reaction.
c.	The Gibbs free energy released from a product-favored reaction is used to provide the energy for a reactant-favored reaction to occur.
d.	A product-favored reaction supplies the activation energy for another reaction.
e.	The Gibbs free energy released from a product-favored reaction is released to the surroundings, causing an increase in entropy.

e^- Chem

____ 50. Which is not an absolute indicator of a redox reaction?

a.	One reactant is a strong oxidizing agent.
b.	One reactant is a strong reducing agent.
c.	At least one element changes oxidation number.
d.	A pure element is present as a reactant or a product.
e.	Oxygen is present.

____ 51. The balanced reaction between aluminum metal and aqueous cadmium(II) ion to produce cadmium metal and aqueous aluminum ion in acidic solution is written

a.	2Al(s) + 3Cd²⁺(aq) ® 2Al³⁺(aq) + 3Cd(s)
b.	3Al(s) + 2Cd²⁺(aq) ® 3Al³⁺(aq) + 2Cd(s)
c.	Al(s) + 3Cd²⁺(aq) ® 2Al³⁺(aq) + Cd(s)
d.	6Al(s) + 6Cd²⁺(aq) ® 6Al³⁺(aq) + 6Cd(s)
e.	2Al(s) + 3Cd²⁺(aq) ® 3Al³⁺(aq) + 2Cd(s)

Use this list of half-reactions to answer the following questions.

MnO₄^-(aq) + 8H⁺(aq) + 5e^- ® Mn²⁺(aq) + 4H₂O(l)	1.51 V
Cr₂O₇^2-(aq) + 6e^-® 2Cr³⁺(aq) + 7H₂O(l)	1.33 V
Pt²⁺(aq) + 2e^-® Pt(s)	1.20 V
Cu²⁺(aq) + 2e^-® Cu(s)	0.34 V
Pb²⁺(aq)+2e^-®Pb(s)	-0.13 V
Al³⁺(aq)+3e^-®Al(s)	-1.66 V

____ 53. Refer to Inst 19-1. Which combination of reactants could be used to make an electrochemical cell?

a.	Al³⁺(aq) and Cu(s)
b.	Pt(s) and Pb²⁺(aq)
c.	Cu(s) and MnO₄^-(aq)
d.	Cr₂O₇^2-(aq) and MnO₄^-(aq)
e.	Al³⁺(aq) and Cr³⁺(aq)

____ 54. The value of for an aluminum-zinc electrochemical cell is 0.897 V at 25°C. Calculate the value of DGº for this cell.

a.	-86.6 kJ
b.	-173 kJ
c.	-260. kJ
d.	-433 kJ
e.	-519 kJ

____ 55. For a zinc-platinum electrochemical cell, calculate the value of when the concentration of Pt²⁺(aq) is 0.050 M and the concentration of Zn²⁺(aq) is 1.1 M. = 1.96 V under standard conditions. Pt is the less active metal.

a.	1.88 V
b.	1.92 V
c.	1.96 V
d.	2.00 V
e.	2.04 V

____ 57. An electrolytic reaction is a system in which

a.	a chemical reaction is used to produce electricity.
b.	electricity is used to produce a chemical reaction.
c.	the same element is both oxidized and reduced.
d.	a reactant-favored reaction is forced to produce electricity by the input of heat or light.
e.	the reaction conditions are manipulated to change the value of to a favorable one.

____ 58. Which statement concerning the number of electrons involved in electrolysis is not correct?

a.	Electrons can be "counted" by multiplying the current in amps by the time in seconds.
b.	The charge associated with one electron is 96,500 coulombs.
c.	In producing one mole of Cl₂(g) from Cl^-(aq), two moles of electrons are produced.
d.	When one mole of Fe is produced from Fe³⁺(aq), three moles of electrons are needed.
e.	Electroplating of one mole of silver from a solution of silver ions requires one mole of electrons.

____ 59. Calculate the time needed to plate out 175 g of nickel from a Ni²⁺ solution when a current of 10.0 A is applied.

a.	938 hr
b.	32 hr
c.	16 hr
d.	8.0 hr
e.	4.0 hr

85. Distinguish between activation energy and the energy required to cause a reactant-favored process to occur.

86. a. Use the data given to determine whether refining aluminum from its ore, which is primarily aluminum oxide, is product favored at 25°C. Be sure to write the balanced equation before attempting to solve this problem.

b. This question could be extended to ask the Kelvin or Celsius temperature at which the transition between product-favored and reactant-favored occurs.

87. Consider the reaction shown, with DG° = -32.8 kJ at 25°C. What is the value of DG when the pressure of nitrogen = 3.5 bar; hydrogen = 1.2 bar; and ammonia = 0.22 bar? Explain the relationship between your answer and the value of DG°; that is, does your answer make sense?

N₂(g) + 3H₂(g) ® 2NH₃(g)

89. Write the two half-reactions for the net redox reaction 2Al₂O₃(s) ® 4Al(s) + 3O₂(g). Explain how they can be used to write the balanced reaction.

90. Write the balanced equation for the reaction between aluminum and dichromate ion in acidic solution to produce aluminum ion and chromium(III) ion.

91. Explain the relationship between the placement of the metals aluminum, zinc, iron, copper, and silver on a table of reduction potentials and in an activity series. The metals are listed in this question in order from most active to least active.

92. Use the table of potentials shown as needed.

Pt²⁺(aq) + 2e^- ® Pt(s) 1.20 V

Cu²⁺(aq) + 2e^- ® Cu(s) 0.34 V

Pb²⁺(aq) + 2e^- ® Pb(s) -0.13 V

Ga³⁺(aq) + 3e^- ® Ga(s) -0.53 V

a. Write the balanced overall reaction for gallium reacting with copper(II) ion.

b. Calculate the value of for the reaction.

c. Determine the number of electrons transferred in this reaction. Explain how you determined this answer.

d. Calculate the value of DG° for this cell at 25°C.

e. Calculate the value of the equilibrium constant for this reaction at 25°C.

f. Is this reaction product-favored or reactant-favored? Explain how your answers in parts b, d, and e support this conclusion.

Nuclear Reactions

____ 60. Gamma radiation is best described as

a.	electrons ejected at high speeds from a radioactive nucleus.
b.	a form of electromagnetic radiation that is unaffected by magnetism.
c.	high-speed particles similar in size to an electron, but oppositely charged.
d.	neutral particles that weigh approximately one atomic mass unit.
e.	positive particles that are identical to the nucleus of an atom of He-4.

____ 61. In the reaction shown, the radiation produced is a(an) _____.

a.	alpha particle
b.	beta particle
c.	gamma ray
d.	neutron
e.	positron

____ 62. All of these are common modes of radioactive decay except __________.

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

____ 63. 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

____ 64. Determine the number of Bq in 55 mCi. 1 Ci = 3.7 ´ 10¹⁰ dps and 1 Bq = 1 dps.

a.	5.5 ´ 10^-5 Bq
b.	1.4 ´ 10^-3 Bq
c.	6.7 ´ 10² Bq
d.	2.0 ´ 10⁶ Bq
e.	2.0 ´ 10¹² Bq

____ 65. An uncontrolled fission reaction occurs in a _____.

a.	nuclear reactor
b.	nuclear bomb
c.	x-ray machine
d.	particle accelerator
e.	cyclotron

94. Explain in your own words why iron is the most abundant heavy element in the universe.

95. "Since radon is an alpha emitter, and alpha particles have a low penetrating power, radon is not really as dangerous as the publicity implies." Is this statement true or false? Support your answer with a detailed explanation.