Deck 18: Chemistry of the Environment

Question 1

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

Answer 1

CFCl₃

Question 2

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 2

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

Question 3

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

Answer 3

fossil-fuel combustion

Question 4

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 5

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 6

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 7

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 8

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 9

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 10

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 11

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 12

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 13

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 14

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 15

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 16

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

A)CO₂
B)SO₂
C)CH₄
D)NO
E)O₃

Question 17

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

Question 18

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 19

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 20

In the past, CFCs were not used in ________.

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

Question 21

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 22

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 23

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 24

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

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

Question 25

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 26

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 27

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 28

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 29

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 30

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 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

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 33

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 34

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 35

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

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

Question 36

THMs are ________.

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

Question 37

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 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)2.62
E)5.25

Question 39

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 40

The main ionic constituent of sea water is ________.

A)Na⁺
B)Cl^-
C)SO₄^2-
D)Mg²⁺
E)Ca²⁺

Question 41

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 42

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

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

Question 43

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

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

Question 44

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 45

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 46

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 47

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 48

Ozone is a(n)________ of oxygen.

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

Question 49

Acid rain typically has a pH of about ________.

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

Question 50

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

Question 51

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

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

Question 52

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

A)Cl₂
B)N₂
C)Ne
D)CO₂
E)H₂O

Question 53

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 54

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 55

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, upper atmosphere

Question 56

CFC stands for ________.

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

Question 57

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 58

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

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

Question 59

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 60

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 61

Components of Air Mole Fraction Nitrogen 0.781
Oxygen 0.209
Argon 0.010
What is the partial pressure or oxygen (in torr)in the atmosphere when the atmospheric pressure is 755.0 torr?

A)158
B)590.
C)611
D)7.55
E)760

Question 62

The mole fraction of nitrogen in dry air near sea level is 0.78084, where the molar mass of nitrogen is 28.013. The partial pressure of nitrogen when the total atmospheric pressure (dry air)is 97.5 kPa is ________ kPa.

A)126
B)4.51
C)77.0
D)2.16 × 10³
E)2.75

Question 63

What is the wavelength of a photon with just enough energy to break a C-Cl bond? (The bond energy of the C-Cl bond is 331 kJ/mole.)

A)362 nm
B)723 nm
C)181 nm
D)5.46 × 10³⁵ nm
E)5.50 × 10^-19 nm

Question 64

The mole fraction of nitrous oxide in dry air near sea level is 0.00000050. The concentration of nitrous oxide is ________ molecules per liter, assuming an atmospheric pressure of 739 torr and a temperature of 29.5 °C.

A)1.5 × 10^-5
B)2.0 × 10^-8
C)1.2 × 10¹⁶
D)8.9 × 10¹⁸
E)1.2 × 10¹⁷

Question 65

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 66

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

A)Cl^-
B)Cl₂
C)HCl
D)HClO
E)H⁺

Question 67

The concentration of water vapor in a sample of air that has a partial pressure of water of 1.20 torr and a total pressure of air of 695 torr is ________ ppm.

A)1.7 × 10³
B)1.7
C)0.17
D)5.8 × 10^-4
E)0.58

Question 68

Components of Air Mole Fraction Nitrogen 0.781
Oxygen 0.209
Argon 0.010
What is the partial pressure or nitrogen (in torr)in the atmosphere when the atmospheric pressure is 760.0 torr?

A)159
B)594
C)611
D)7.60
E)760

Question 69

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

A)NO₂
B)N₂O₄
C)CO
D)SO₂
E)CO₂

Question 70

A sample of air from a home is found to contain 7.2 ppm of carbon monoxide. This means that if the total pressure is 695 torr, then the partial pressure of CO is ________ torr.

A)5.0 × 10³
B)5.0 × 10^-3
C)5.0
D)1.0 × 10⁴
E)9.7 × 10⁷

Question 71

The area of the Earth's atmosphere 50 - 85 km above the surface is called the ________.

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

Question 72

What is the percentage of freshwater on planet Earth?

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

Question 73

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 74

The concentration of ozone in a sample of air that has a partial pressure of O₃ of 0.53 torr and a total pressure of air of 695 torr is ________ ppm.

A)7.6 × 10²
B)0.76
C)0.076
D)1.3 × 10^-3
E)1.3

Question 75

The "scale" caused by hard water is ________.

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

Question 76

The concentration of carbon monoxide in a sample of air is 6.0 ppm. There are ________ molecules of CO in 1.00 L of this air at 755 torr and 23 °C.

A)2.5 × 10^-7
B)1.4 × 10²¹
C)1.9 × 10¹⁸
D)1.1 × 10²⁰
E)1.5 × 10¹⁷

Question 77

The mole fraction of krypton in dry air near sea level is 0.00000114 where the molar mass of krypton is 83.80. The concentration of krypton in the atmosphere is ________ ppm.

A)8.77 × 10¹¹
B)1.14 × 10^-4
C)1140
D)1.14
E)1.14 × 10^-12

Question 78

Which of the following is (are)not a typical source of nitric oxide?

A)livestock emissions
B)atmospheric electrical discharges
C)internal combustion engines
D)combustion of organic matter
E)all of the above

Question 79

The concentration of a gas is 3.18 × 10³ ppm at in a container where its partial pressure is 0.591 torr. The total pressure inside the container must be

A)1.86 × 10^-10
B)5.38 × 10^-3
C)1.86 × 10^-4
D)1.88 × 10³
E)1.88 × 10⁹

Question 80

The partial pressure of a gas in air is 1.87 torr and its concentration is 8.57 × 10³ ppm. The total air pressure is ________ torr.

A)218
B)1.60 × 10^-2
C)2.18 × 10^-4
D)4.58 × 10⁹
E)0.218