Deck 18: Chemistry of the Environment

Question 1

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) there is an excess of oxygen
D) the carbon- containing material is a gas
E) the combustion flame is too hot

Answer 1

there is insufficient oxygen to convert all of the carbon to carbon dioxide

Question 2

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

Answer 2

make the water slightly basic so that addition of Al₂(SO₄)₃ will afford a gelatinous precipitate of Al(OH)₃

Question 3

What is meant by the salinity of seawater?

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

Answer 3

mass in grams of dry salts present in 1 kg of seawater

Question 4

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) mesosphere < troposphere < thermosphere < stratosphere
D) troposphere < stratosphere < mesosphere < thermosphere
E) troposphere < mesosphere < thermosphere < stratosphere

Question 5

Carbon dioxide contributes to atmospheric warming by .

A) absorbing radiation emitted from the surface of the earth preventing its loss to space
B) absorbing incoming radiation from the sun and converting it to heat
C) 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
D) reducing the concentration of CO in the atmosphere.
E) undergoing exothermic reactions extensively in the atmosphere

Question 6

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

Question 7

Biodegradable material degraded by aerobic processes ends up as _.

A) CH₄
B) SO₄^2-
C) H₂S
D) PH₃
E) NH₃

Question 8

The dissociation energy of the C- Cl bond in CF₃Cl is 339 kJ/mol. The maximum wavelength of light that has enough energy per photon to dissociate the C- Cl bond is _ nm.

A) 3.53 × 10^{- 7}
B) 353
C) 3.53 × 10^{- 4}
D) 1130
E) 3.53 × 10⁵

Question 9

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

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

Question 10

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

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

Question 11

The mole fraction of oxygen in dry air near sea level is 0.20948. The concentration of oxygen is
Molecules per liter, assuming an atmospheric pressure of 739 torr and a temperature of 29.5°C.

A) 5.07 × 10²²
B) 6.23
C) 0.00819
D) 4.93 × 10²¹
E) 3.75 × 10²⁴

Question 12

THMs are .

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

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?

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

Question 14

Photoionization processes (e.g., N₂ + hv - 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) O₂ + hv → 2O
B) NO + O₂ + hv → NO₃
C) N₂ + hv →2N
D) N₂ + O₂ + hv → 2NO
E) O₃ + hv →O₂ + O

Question 15

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

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

Question 16

Why is carbon monoxide toxic?

A) It binds to hemoglobin, thus blocking the transport of oxygen.
B) It causes renal failure.
C) It binds to oxygen and causes suffocation.
D) It induces leukemia.
E) It blocks acetylcholine receptor sites causing paralysis and rapid death.

Question 17

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

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

Question 18

Eutrophication of a lake is the process of .

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

Question 19

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

Question 20

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

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

Question 21

Organic matter is a source for all of the following atmospheric gases, except .

A) SO₂
B) CO₂
C) NO
D) CO
E) CH₄

Question 22

The ionization energy of O₂ is 1205 kJ/mol:

The maximum wavelength of light capable of causing the ionization of O₂ is nm.

A) 4017
B) 9.94 × 10^{- 5}
C) 99.4
D) 9.94 × 10^{- 8}
E) 9.94 × 10⁴

Question 23

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) 8.9 × 10³
C) 4.3 × 10^{- 3}
D) 1.1 × 10⁸
E) 4.3

Question 24

The mole fraction of neon in dry air near sea level is 1.818 × 10^{- 5} where the molar mass of neon is
20)183. The concentration of neon in the atmosphere is _ _ ppm.

A) 1.818 × 10^{- 11}
B) 1.818 × 10⁴
C) 18.18
D) 5.50 × 10¹⁰
E) 0.001818

Question 25

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

A) SO₃
B) SO₂
C) SO
D) H₂SO₄
E) H₂S

Question 26

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

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

Question 27

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

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

Question 28

In the past, CFCs were not used in .

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

Question 29

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

A) SO₂ (g) + H₂O (l) →H₂SO₃ (aq)
B) SO₂ (g) + H₂O (l) →H₂SO₄ (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 30

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

A) He
B) O₂
C) CFCl₃
D) N₂
E) CO₂

Question 31

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) The radiation in the stratosphere dissociates them producing chlorine atoms that catalytically destroy ozone.
D) They are greenhouse gases that raise the temperature above the dissociation temperature of ozone.
E) CFCs do not damage the ozone.

Question 32

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

Question 33

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

Question 34

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 35

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

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

Question 36

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

A) NH₄⁺
B) NO₃^-
C) NH₃
D) NO
E) NO₂

Question 37

What is the final stage in municipal water treatment?

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

Question 38

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

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

Question 39

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

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

Question 40

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

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

Question 41

The contribution of sulfur to acid rain is via the production of .

Question 42

The concentration of Br^- in a sample of seawater is 8.3 × 10^{- 4} M. If a liter of seawater has a mass of
1)0 kg, the concentration of Br^- - is ppm.

A) 0.066
B) 8.3
C) 8.3 × 10^{- 6}
D) 66
E) 0.83

Question 43

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

Question 44

Clean rainwater is acidic mainly due to the presence of .

Question 45

The approximate pH of acid rain is _ .

Question 46

The average pH of the oceans is and is maintained by the buffering capacity of
.

Question 47

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

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

Question 48

To reduce lead toxicity, the metal, , is used in the electrodeposition of automobiles to prevent corrosion.

Question 49

Show how a molecule of C₂F₂Cl₂ can destroy two molecules of ozone, O₃.

Question 50

The three most concentrated ions in seawater are .

Question 51

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

Question 52

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

A) Kr
B) O₂
C) H₂O
D) N₂
E) He

Question 53

The average adult in the U.S. needs _ liters of water per day.

Question 54

In the equation below, what is the meaning of the asterisk? O + O₂ →O₃^*

Question 55

Approximately 90% of the earth's ozone is in the .

Question 56

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

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

Question 57

The fourth most abundant component of dry air is .

Question 58

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

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

Question 59

Water containing high concentrations of cations is called hard water.

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

Question 60

The concentration of ozone in Los Angeles is 0.67 ppm on a summer day. This means that if the total pressure is 735 torr, then the partial pressure of O₃ is _ torr.

A) 0.49
B) 1.1 × 10⁹
C) 4.9 × 10^{- 4}
D) 4.9 × 10²
E) 9.1 × 10²

Question 61

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

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

Question 62

The amount of atomic O relative to O₂ .

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

Question 63

Acid rain typically has a pH of about .

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

Question 64

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

A) Ne
B) Cl₂
C) H₂O
D) N₂
E) CO₂

Question 65

What is the partial pressure or oxygen (in torr) in the atmosphere when the atmospheric pressure is 760 torr?

A) 430
B) 601
C) 159
D) 720
E) 760

Question 66

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

A) Cl₂
B) Cl^-
C) HCl
D) H⁺
E) HClO

Question 67

The pressure of the atmosphere .

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

Question 68

Ozone is a(n) of oxygen.

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

Question 69

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

A) NO₂
B) SO₂
C) N₂O₄
D) CO₂
E) CO

Question 70

The liquid portion of the Earth is called the _ _.

A) atmosphere
B) lithosphere
C) mesosphere
D) stratosphere
E) hydrosphere

Question 71

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

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

Question 72

The world's largest desalinization plant is in _ and uses the process of
to produce drinking water.

Question 73

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

A) O₂
B) CO
C) H₂O
D) CO₂
E) H₂O₂

Question 74

Ozone is a necessary, protective component of the

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

Question 75

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

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

Question 76

A chemical bond rupture from the absorption of a photon is called _.

Question 77

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

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

Question 78

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

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

Question 79

The concept that radiowave propagation was affected by the atmosphere of the earth was discovered by _ .

Question 80

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

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