Deck 18: Chemistry of the Environment

Question 1

The majority of ozone that protects against the high energy radiation of the sun is found in the __________.

A)thermosphere
B)mesosphere
C)mesopause
D)stratosphere
E)troposphere

Answer 1

stratosphere

Question 2

What is the wavelength of a photon with just enough energy to break a CN bond? (The bond energy of the CN bond is 891 kJ/mole.)

A)242 nm
B)304 nm
C)134 nm
D)186 nm
E)275 nm

Answer 2

134 nm

Question 3

Why are chlorofluorocarbons so damaging to the ozone layer when they are such stable molecules?

A)They contain a double bond that ozone readily attacks, resulting in the destruction of the ozone.
B)They are very light molecules that rapidly diffuse into the upper atmosphere and block the radiation that causes formation of ozone.
C)They are greenhouse gases that raise the temperature above the dissociation temperature of ozone.
D)The radiation in the stratosphere dissociates them producing chlorine atoms that catalytically destroy ozone.
E)CFCs do not damage the ozone.

Answer 3

The radiation in the stratosphere dissociates them producing chlorine atoms that catalytically destroy ozone.

Question 4

In the troposphere, temperature __________ with increasing altitude, while in the stratosphere, temperature __________ with increasing altitude.

A)increases, increases
B)decreases, decreases
C)increases, decreases
D)decreases, increases
E)decreases, remains constant

Question 5

Select the substance that is thought to be partially responsible for depleting the concentration of ozone in the stratosphere.

A)CFCl₃
B)CO₂
C)O₂
D)N₂
E)He

Question 6

Which of the following is arranged correctly in order of increasing distance from Earth's surface?

A)mesosphere < troposphere < stratosphere < thermosphere
B)troposphere < mesosphere < stratosphere < thermosphere
C)troposphere < mesosphere < thermosphere < stratosphere
D)troposphere < stratosphere < mesosphere < thermosphere
E)mesosphere < troposphere < thermosphere < stratosphere

Question 7

In the past, CFCs were not used in __________.

A)spray cans
B)plastic manufacturing
C)air conditioners
D)refrigerators
E)dry cleaning

Question 8

Which of the following is (are)not a typical source of carbon dioxide?

A)decomposition of organic matter
B)release from oceans
C)combustion of fossil fuels
D)atmospheric electrical discharges
E)all of the above

Question 9

Why does ozone not form in high concentrations in the atmosphere above 50 km?

A)Insufficient oxygen is available.
B)Insufficient molecules exist for removal of excess energy from ozone upon its formation.
C)Light of the required wavelength is not available at those altitudes.
D)Atomic oxygen concentration is too low at high altitudes.
E)The pressure is too high.

Question 10

Of the reactions involved in the photodecomposition of ozone (shown below), which are exothermic?1. O₂ (g)+ hν → O (g)+ O (g) 2. O (g)+ O₂ (g)+ M (g)→ O₃(g)+ M^* (g)
3. O₃ (g)+ hν → O₂ (g)+ O (g)
4. O (g)+ O (g)+ M (g)→ O₂ (g)+ M^* (g)

A)2 and 4
B)1 and 3
C)1, 2, and 4
D)2 only
E)all of them

Question 11

Why does the upper atmosphere contain only very little dissociated nitrogen?

A)most of the nitrogen is in the troposphere and not in the upper atmosphere
B)the dissociated nitrogen very rapidly diffuses out of the atmosphere and into space
C)nitrogen atoms are extremely reactive and so react with other substances immediately upon their formation
D)the bond energy of nitrogen is very high and it does not absorb radiation very efficiently
E)There is no N₂ in the upper atmosphere.

Question 12

Cl atoms formed via photolysis of C-Cl bonds of chlorofluorocarbons in the stratosphere are particularly effective in destroying ozone at these altitudes because __________.

A)Cl atoms absorb UV, which generate O atoms to react with O₂ to produce ozone
B)Cl atoms catalytically convert O₃ to O₂
C)Cl atoms stoichiometrically convert O₃ to O₂
D)Cl atoms react with H atoms, which catalyze conversion of O₂ to O₃
E)Cl atoms react with N atoms, which catalyze conversion of O₂ to O₃

Question 13

As one gains altitude in the atmosphere, based on the ionization energies shown below, which sequence of mole fractions is the correct one? Process Ionization Energy (kJ/mol)
N₂ + hν → N₂⁺ + e^- 1495
O₂ + hν → O₂⁺ + e^- 1205
O + hν → O⁺ + e^- 1313
NO + hν → NO⁺ + e^- 890

A)N₂ > N > NO > O₂
B)N₂ > O > O₂ > NO
C)N₂ > O₂ > O > NO
D)NO > O₂ > O > N₂
E)All will be equal.

Question 14

Photoionization processes (e.g., N₂ + hν → N₂⁺ + e^-)remove UV of <150 nm. Which photoreaction is the principal absorber of UV in the 150-200 nm range in the upper atmosphere?

A)N₂ + hν → 2N
B)O₂ + hν → 2O
C)O₃ + hν → O₂ + O
D)N₂ + O₂ + hν → 2NO
E)NO + O₂ + hν → NO₃

Question 15

In the reactions involved in the photodecomposition of ozone (shown below), what does M symbolize? 1. O₂ (g)+ hν → O (g)+ O (g)
2. O (g)+ O₂ (g)+ M (g)→ O₃ (g)+ M^* (g)
3. O₃ (g)+ hν → O₂ (g)+ O (g)
4. O (g)+ O (g)+ M (g)→ O₂ (g)+ M^* (g)

A)mesosphere
B)metal
C)molybdenum
D)methane
E)molecule

Question 16

The partial pressure of a gas in air is 1.20 torr and its concentration is 2.80 x 10³ ppm. The total air pressure is __________ torr.

A)1.2
B)429
C)760
D)2333
E)2800

Question 17

Which of the following is not released by the combustion of fossil fuels?

A)CO₂
B)SO₂
C)CH₄
D)NO
E)O₃

Question 18

The area of the Earth's atmosphere 10-50 km above the surface is called the __________.

A)thermosphere
B)mesosphere
C)mesopause
D)stratosphere
E)troposphere

Question 19

Of the compounds below, the one that requires the shortest wavelength for photoionization is __________.

A)O
B)O₂
C)NO
D)N₂
E)They all require the same wavelength.

Question 20

Of the reactions involved in the photodecomposition of ozone (shown below), which are photochemical? 1. O₂ (g)+ hν → O (g)+ O (g)
2. O (g)+ O₂ (g)+ M (g)→ O₃ (g)+ M^* (g)
3. O₃ (g)+ hν → O₂ (g)+ O (g)
4. O (g)+ O (g)+ M (g)→ O₂ (g)+ M^* (g)

A)2 and 4
B)1, 2, and 4
C)1 and 3
D)1 only
E)all of them

Question 21

Which of the following is not a stage in water treatment?

A)coarse filtration
B)aeration
C)chlorination
D)distillation
E)settling

Question 22

Sulfur released into the troposphere arises from both natural and human activity. What is the ratio of human to natural sources of sulfur compounds?

A)3:1
B)2:1
C)1:1
D)1:2
E)1:3

Question 23

Which one of the following substances found in the atmosphere will absorb radiation in the infrared portion of the spectrum?

A)N₂
B)O₂
C)Kr
D)H₂O
E)He

Question 24

The source(s)of sulfur dioxide in the atmosphere is/are __________.

A)volcanic gases
B)forest fires
C)bacterial action
D)fossil-fuel combustion
E)all of the above

Question 25

How does lime reduce sulfur dioxide emissions from the burning of coal?

A)It reacts with the sulfur dioxide to form calcium sulfite solid that can be precipitated.
B)It reduces the sulfur dioxide to elemental sulfur that is harmless to the environment.
C)It oxidizes the sulfur dioxide to tetrathionate that is highly water soluble so it can be scrubbed from the emission gases.
D)It catalyzes the conversion of sulfur dioxide to sulfur trioxide which is much less volatile and can be removed by condensation.
E)It converts SO₂ to solid, elemental sulfur.

Question 26

In the presence of oxygen, the nitrogen present in biodegradable material ends up mainly as __________.

A)NH₃
B)NH₄⁺
C)NO
D)NO₂
E)NO₃^-

Question 27

The cumulative result of carbon dioxide, methane, and ozone in the troposphere on atmospheric temperatures is referred to as __________.

A)acid rain
B)the greenhouse effect
C)photoionization
D)photochemical smog
E)photodissociation

Question 28

Which one of the following is a source of carbon dioxide in the troposphere?

A)natural gas seepage
B)electrical discharges
C)fossil-fuel combustion
D)volcanic gases
E)forest fires

Question 29

A single individual typically uses the greatest quantity of water for __________.

A)flushing toilets
B)cooking
C)cleaning (bathing, laundering, and house cleaning)
D)watering lawns
E)drinking water

Question 30

The main ionic constituent of sea water is __________.

A)Na⁺
B)Cl^-
C)SO₄^-2
D)Mg⁺²
E)Ca⁺²

Question 31

The reaction that forms most of the acid in acid rain is __________.

A)SO₂ (g)+ H₂O (l)→ H₂SO₄ (aq)
B)SO₂ (g)+ H₂O (l)→ H₂SO₃ (aq)
C)H₂S (g)+ 2 O₂ (g)→ H₂SO₄ (l)
D)Cl₂ (g)+ H₂O (l)→ HCl (aq)+ HClO (aq)
E)SO₃ (g)+ H₂O (l)→ H₂SO₄ (aq)

Question 32

To produce acceptable quality drinking water from seawater by desalination, the level of salt must be reduced __________ fold.

A)10
B)50
C)70
D)100
E)120

Question 33

Which gaseous sulfur compound combines with water to form the principal acidic constituent of acid rain?

A)H₂SO₄
B)SO₂
C)SO
D)SO₃
E)H₂S

Question 34

What is the final stage in municipal water treatment?

A)filtration through sand and gravel
B)aeration
C)settling
D)treatment with ozone or chlorine
E)removal of added fluoride

Question 35

The primary detrimental effect of the presence of large amounts of biodegradable organic materials in water is __________.

A)it causes death of bottom dwelling organisms because it agglutinates and settles to the bottom, poisoning bottom dwelling organisms
B)it causes oxygen depletion in the water
C)it rises to the surface and absorbs wavelengths needed by aquatic plants
D)it decomposes endothermically causing the temperature of the water to decrease below the limits within which most aquatic organisms can live
E)it causes the water to become murky

Question 36

Carbon dioxide contributes to atmospheric warming by __________.

A)absorbing incoming radiation from the sun and converting it to heat
B)absorbing radiation emitted from the surface of the earth preventing its loss to space
C)undergoing exothermic reactions extensively in the atmosphere
D)increasing the index of refraction of the atmosphere so that infrared radiation from the sun is refracted to the surface of the earth where it is converted to heat
E)reducing the concentration of CO in the atmosphere.

Question 37

Of the following, only __________ does not result in the formation of acid rain.

A)carbon dioxide
B)nitrogen dioxide
C)sulfur dioxide
D)nitrogen monoxide
E)methane

Question 38

The concentration of Mg in seawater is 0.054 M. How many grams of Mg can be extracted from 10.0 kg of seawater if the recovery rate is 20.0%?

A)13.9
B)6.50
C)11.3
D)2.60
E)5.25

Question 39

What is meant by the salinity of seawater?

A)percent by mass of salt in seawater
B)mass in grams of dry salts present in 1 kg of seawater
C)molality of NaCl in seawater
D)osmotic pressure of seawater
E)molarity of NaCl in seawater

Question 40

Incomplete combustion of carbon-containing materials occurs when __________.

A)there is insufficient oxygen to convert all of the carbon to carbon dioxide
B)there are sulfur impurities in the carbon-containing material
C)the carbon-containing material is a gas
D)the combustion flame is too hot
E)there is an excess of oxygen

Question 41

Chemical treatment of municipal water supplies commonly entails use of CaO, Al₂(SO₄)₃, and Cl₂. The purpose of adding CaO is to __________.

A)remove all HCO₃^- as solid CaCO₃
B)remove all SO₄^2- as solid CaSO₄
C)remove all Cl^- as solid CaCl₂
D)selectively kill anaerobic (but not aerobic)bacteria
E)make the water slightly basic so that addition of Al₂(SO₄)₃ will afford a gelatinous precipitate of Al(OH)₃

Question 42

Of the noble gases, __________ is present in highest concentration in dry air at sea level.

A)Ne
B)He
C)Xe
D)Kr
E)Ar

Question 43

Eutrophication of a lake is the process of __________.

A)rapid increase in the amount of dead and decaying plant matter in the lake as a result of excessive plant growth
B)rapid decline in the lake's pH due to acid rain
C)dissolved oxygen being depleted by an overpopulation of fish
D)stocking the lake with fish
E)restoration of the lake's dissolved oxygen supply by aerobic bacteria

Question 44

The amount of atomic O relative to O₂ __________.

A)is highest in the troposphere
B)is highest in the stratosphere
C)increases with altitude in the thermosphere
D)decreases with altitude in the thermosphere
E)is essentially independent of altitude in the thermosphere

Question 45

In the equation below, M is most likely __________. O + O₂ + M → O₃ + M^*

A)Cl₂
B)N₂
C)Ne
D)CO₂
E)H₂O

Question 46

THMs are __________.

A)non-toxic
B)natural
C)used in green chemistry
D)suspected carcinogens
E)atmospheric pollutants

Question 47

Natural, unpolluted rainwater is typically acidic. What is the source of this natural acidity?

A)CO₂
B)SO₂
C)NO₂
D)HCl
E)chlorofluorocarbons

Question 48

Water containing high concentrations of __________ cations is called hard water.

A)Ca²⁺
B)Mg²⁺
C)Na⁺
D)K⁺
E)Ca²⁺ or Mg²⁺

Question 49

The pressure of the atmosphere __________.

A)increases with altitude
B)follows the same trend as temperature
C)decreases with altitude
D)follows the reverse trend as temperature
E)stays the same

Question 50

CFC stands for __________.

A)chlorinated freon compound
B)chlorofluorocarbon
C)carbonated fluorine compound
D)caustic fluorine carbohydrate
E)carbofluoro compound

Question 51

Ozone is a(n)__________ of oxygen.

A)isomer
B)allotrope
C)isotope
D)resonance structure
E)atomic form

Question 52

The layer of the atmosphere that contains our weather is called the __________.

A)mesosphere
B)heterosphere
C)stratosphere
D)thermosphere
E)troposphere

Question 53

Which one of the following could be produced by anaerobic bacteria decomposing biodegradable waste?

A)nitrate
B)sulfate
C)carbon dioxide
D)hydrogen sulfide
E)water

Question 54

The dividing line between the troposphere and stratosphere is known as the __________.

A)mesosphere
B)tropopause
C)thermosphere
D)stratopause
E)mesopause

Question 55

What is/are the product(s)of photodissociation of molecular oxygen?

A)molecular nitrogen
B)excited oxygen molecules
C)ozone
D)ozone and atomic oxygen
E)atomic oxygen

Question 56

Which of the following is not one of the 12 principles associated with green chemistry?

A)use of renewable feedstocks
B)design of safer chemicals
C)less hazardous chemical synthesis
D)design for degradation
E)reduction in the use of catalytic reagents

Question 57

The C-Cl and C-F bond dissociation energies in CF₃Cl are 339 kJ/mol and 482 kJ/mol, respectively. The maximum wavelengths of electromagnetic radiation required to rupture these bonds are __________ and __________, respectively.

A)45.0 nm, 307 nm
B)742 nm, 654 nm
C)482 nm, 248 nm
D)353 nm, 248 nm
E)979 nm, 953 nm

Question 58

The lime-soda process is used for large-scale water-softening operations. CaO is added to __________.

A)oxidize Fe²⁺ to insoluble Fe₂O₃
B)cause precipitation of magnesium as Mg(OH)₂
C)remove most Al³⁺ as solid Al(OH)₃
D)cause precipitation of iron and magnesium as Fe₂MgO₄
E)reduce the pH to 3-4

Question 59

The C-O bond dissociation energy in CO₂ is 799 kJ/mol. The maximum wavelength of electromagnetic radiation required to rupture this bond is __________.

A)307 nm
B)149 nm
C)248 nm
D)353 nm
E)979 nm

Question 60

Which of the following is classified as a supercritical fluid?

A)water
B)xylene
C)toluene
D)hydrogen peroxide
E)none of the above

Question 61

Radiation in the infrared portion of the spectrum is absorbed by __________ found in the atmosphere.

A)N₂
B)O₂
C)CO₂
D)Ar
E)He

Question 62

The brown color of photochemical smog over a city is mainly due to __________.

A)NO₂
B)N₂O₄
C)CO
D)SO₂
E)CO₂

Question 63

The mole fraction of carbon dioxide in dry air near sea level is 0.000375, where the molar mass of carbon dioxide is 44.010. The partial pressure of carbon dioxide when the total atmospheric pressure (dry air)is 97.5 kPa is __________ kPa.

A)2.63 × 10⁵
B)5.97 × 10³
C)0.0370
D)1.63
E)8.40 × 10^-4

Question 64

The concentration of which greenhouse gas has increased steadily over the last few decades?

A)H₂O
B)CO
C)CO₂
D)H₂O₂
E)O₂

Question 65

The sterilizing action of chlorine in water is due to what substance?

A)Cl^-
B)Cl₂
C)HCl
D)HClO
E)H⁺

Question 66

A sample of air from a home is found to contain 6.2 ppm of carbon monoxide. This means that if the total pressure is 695 torr, then the partial pressure of CO is __________ torr.

A)4.3 × 10³
B)4.3 × 10^-3
C)4.3
D)8.9 × 10³
E)1.1 × 10⁸

Question 67

Ozone is a necessary, protective component of the __________, but is considered a pollutant in the __________.

A)troposphere, upper atmosphere
B)troposphere, air
C)photochemical smog, air we breathe
D)upper atmosphere, troposphere
E)air we breathe

Question 68

The concentration of ozone in a sample of air that has a partial pressure of O₃ of 0.33 torr and a total pressure of air of 735 torr is __________ ppm.

A)4.5 × 10²
B)0.45
C)0.045
D)2.2 × 10^-3
E)2.2

Question 69

Sulfur dioxide is not released into the atmosphere in any significant amount by __________.

A)burning of coal
B)bacterial action
C)internal combustion engines
D)volcanic eruption
E)Sulfur dioxide is produced in significant amount by all of these processes.

Question 70

What is the percentage of freshwater on planet Earth?

A)97%
B)2.1%
C)2.8%
D)0.6%
E)100%

Question 71

The majority of SO₂ released annually in the United States results from __________.

A)combustion of oil
B)acid rain
C)combustion of coal
D)depletion of ozone by CFCs
E)all of the above

Question 72

The mole fraction of helium in dry air near sea level is 0.00000524 where the molar mass of helium is 4.003. The concentration of helium in the atmosphere is __________ ppm.

A)1.91 × 10¹¹
B)5.24 × 10^-4
C)5240
D)5.24
E)5.24 × 10^-12

Question 73

Compounds found in fossil fuels that contain __________ are primarily responsible for acid rain.

A)sulfur
B)carbon
C)hydrogen
D)phosphorus
E)neon

Question 74

What compound in limestone and marble is attacked by acid rain?

A)hydroxyapatite
B)calcium carbonate
C)gypsum
D)graphite
E)potassium hydroxide

Question 75

Acid rain typically has a pH of about __________.

A)7
B)5
C)4
D)2
E)1

Question 76

The concentration of water vapor in a sample of air that has a partial pressure of water of 0.91 torr and a total pressure of air of 735 torr is __________ ppm.

A)1.2 × 10³
B)1.2
C)0.12
D)8.1 × 10^-4
E)0.81

Question 77

The concentration of carbon monoxide in a sample of air is 9.2 ppm. There are __________ molecules of CO in 1.00 L of this air at 755 torr and 23 °C.

A)3.8 × 10^-7
B)2.2 × 10²¹
C)2.9 × 10¹⁸
D)1.7 × 10²⁰
E)2.3 × 10¹⁷

Question 78

In the world's oceans, the average salinity is about __________ g/kg.

A)0.03
B)0.1
C)35
D)17
E)3.5

Question 79

The "scale" caused by hard water is __________.

A)calcium ions
B)calcium carbonate
C)chloride ions
D)magnesium oxalate
E)magnesium ions

Question 80

CO₂ from hydrocarbon combustion creates a major environmental problem that is described as __________.

A)the greenhouse effect
B)photochemical smog
C)acid rain
D)stratospheric ozone depletion
E)all of the above