18) Acid rain typically has a pH of about ________.
A) 7
B) 5
C) 4
D) 2
E) 1
19) 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.
20) 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
21) The brown color of photochemical smog over a city is mainly due to ________.
A) NO2
B) N2O4
C) CO
D) SO2
E) CO2
22) The concentration of which greenhouse gas has increased steadily over the last few decades?
A) H2O
B) CO
C) CO2
D) H2O2
E) O2
23) What is the percentage of freshwater on planet Earth?
A) 97%
B) 2.1%
C) 2.8%
D) 0.6%
E) 100%
24) 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
25) The sterilizing action of chlorine in water is due to what substance?
A) Cl–
B) Cl2
C) HCl
D) HClO
E) H+
26) The “scale” caused by hard water is ________.
A) calcium ions
B) calcium carbonate
C) chloride ions
D) magnesium oxalate
E) magnesium ions
1) 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
2) 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
3) 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
4) 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
5) 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
6) 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
7) 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
8) 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
9) 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
10) 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
11) 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
12) 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
13) 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
14) 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
15) Components of Air Mole Fraction
Nitrogen 0.781
Oxygen 0.209
Argon 0.010
What is the partial pressure or argon (in torr) in the atmosphere when the atmospheric pressure is 750.0
torr?
A) 157
B) 586
C) 611
D) 7.50
E) 760
16) The dissociation energy of N2 is 941 kJ/mol. The maximum wavelength of light that has enough
energy per photon to dissociate the N2 molecule is ________ nm.
A) 3137
B) 1.27 × 10-4
C) 1.27 × 10-7
D) 1.27 × 105
E) 127
17) The ionization energy of NO is 890 kJ/mol:
NO + hv → NO+ + e–
The maximum wavelength of light capable of causing the ionization of NO is ________ nm.
A) 2967
B) 1.35 × 10-4
C) 1.35 × 10-7
D) 134.5
E) 1.35 × 105
18) The concentration of Br– in a sample of seawater is 5.3 × 10-4 M. If a liter of seawater has a mass of 1.0
kg, the concentration of Br– is ________ ppm.
A) 0.042
B) 42
C) 0.53
D) 5.3
E) 0.0053
19) What is the final stage in municipal water treatment?
A) treatment with ozone or chlorine
B) course filtration through a screen
C) addition of CaO/Al2(SO4)3 and settling
D) sand bed filtration
E) aeration
20) In the presence of oxygen, the nitrogen present in biodegradable material ends up mainly as ________.
A) NO3–
B) NO2
C) N2O
D) NH3
E) NH4+
21) Which one of the following is produced by anaerobic bacteria after decomposing biodegradable
nitrogen-containing waste?
A) NH3
B) NO2
C) N2O
D) NO3–
E) NH4+
22) Which process in the Global Water Cycle involves the phase transition H2O (l) → H2O (g)?
A) evaporation from fresh water
B) fog drip
C) plant uptake
D) freshwater storage
E) snowmelt runoff to streams
23) Which choice is one of the suspected carcinogens by–products from water chlorination called THMs?
A) CHClBr2
B) Cl2
C) Br2
D) CH3OCH3
E) CH4
24) Which choice is not one of the Ionic Constituents of seawater typically present in concentrations
greater than 1 ppm?
A) ClO4–
B) Sr2+
C) Na+
D) H3Bo3
E) Cl–
25) The acidic water of a lake (V = 4 × 108 L) must be neutralized with lime, CaO. It will require a
minimum of ______ grams of lime to adjust the pH from 5.6 to 6.5.
A) 2 × 104
B) 5 × 104
C) 1 × 105
D) 3 × 104
E) 5
26) Which of the following is not one of the 12 principles associated with green chemistry?
A) distribution of chemical by-products into oceans
B) less hazardous chemical syntheses
C) promotion of the use of catalysts
D) use of renewable feedstocks
E) inherently safer chemistry for accident prevention
18.4 Short Answer Questions
1) The fourth most abundant component of dry air is ________.
2) A chemical bond rupture resulting from the absorption of a photon is called ________.
3) The concept that radiowave propagation was affected by the atmosphere of the earth was discovered
by ________.
4) In the equation below, what is the meaning of the asterisk?
O + O2 → O3*
5) Approximately 90% of the earth’s ozone is in the ________.
6) Show how a molecule of C2F2Cl2 can destroy two molecules of ozone, O3.
7) In addition to nitrogen oxides, ________ are a major contributor to the depletion of the ozone layer.
8) Clean rainwater is acidic mainly due to the presence of ________.
9) The approximate pH of acid rain is ________.
10) The contribution of sulfur to acid rain is via the production of ________.
11) The primary chemical pollutants that create acid rain are ________ dioxide and ________ oxides.
12) Nitric oxide arises from auto emissions and reacts with oxygen to produce ________ which reacts with
sunlight to produce ________ atoms which react with oxygen to produce ________.
13) The salinity, density, and temperature of seawater varies with ________.
14) The three most concentrated ions in seawater are ________.
15) The average pH of the oceans is ________ and is maintained by the buffering capacity of ________.
16) The average adult in the U.S. needs ________ liters of water per day for drinking.
17) The world’s largest desalinization plant is in ________ and uses the process of ________ to produce
drinking water.
18) The production of dead and decaying plant material is a process called ________.
19) In the purification of drinking water, the filtered water is made basic by adding ________, then
particles and bacteria are captured by adding ________.
18.5 True/False Questions
1) When dealing with gases, the volume fraction and the mole fraction are the same.
2) The bond energy of oxygen is higher than that of nitrogen.
3) The partial pressure of a component in a gas mixture is the product of its mole fraction and the total
mixture pressure.
4) Nitrogen oxides catalytically destroy ozone.
5) Ozone depletion from chlorofluorocarbons is chiefly due to the production of free chlorine.
6) Nitric oxide arises from internal combustion engines.
7) Sulfur compounds in the atmosphere are equally derived from natural sources and from human
activity.
8) The greenhouse effect of a methane molecule far exceeds the effect of a carbon dioxide molecule.
9) The principal component of smog is sulfur dioxide.
10) Most fresh water in the U.S. is used for agriculture.
11) Municipal water treatment consists of five steps ending with chlorination.
18.6 Essay Questions
1) Describe the process of reverse osmosis that is used to desalinate seawater.
2) How can the presence of biodegradable waste in a lake result in the death of fish in the lake?
3) List two of the three major sources of nitrogen and phosphorus in water.
4) Ozone is more efficient at killing bacteria in water, yet chlorine is used more commonly for that
purpose in municipal water treatment. Why?