Solutions Manual for
Chemistry & Chemical
Reactivity 11th Edition By John
Kotz, Paul Treichel, John
Townsend, David Treichel (All
Chapters 1-25, 100% Original
Verified, A+ Grade)
All Chapters Arranged
Reverse: 25-1
Part 1: Instructor Solutions Manual
Part 2: Student Solutions Manual
, Solution and Answer Guide: Kotz Treichel Townsend Treichel, Chemistry and Chemical Reactivity 11e, 978-0-357-85140-1,
Chapter 25: Environmental Chemistry—Earth’s Environment, Energy, and Sustainability
Solution and Answer Guide
Kotz Treichel Townsend Treichel, Chemistry and Chemical Reactivity 11e, 978-0-357-85140-1,
Chapter 25: Environmental Chemistry—Earth’s Environment, Energy, and Sustainability
TABLE OF CONTENTS
Think–Pair–Share ....................................................................................................................................... 2
Part 1: Instructor Solutions Manual: Chapter 25-1
© 2024 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly 1
accessible website, in whole or in part.
, Solution and Answer Guide: Kotz Treichel Townsend Treichel, Chemistry and Chemical Reactivity 11e, 978-0-357-85140-1,
Chapter 25: Environmental Chemistry—Earth’s Environment, Energy, and Sustainability
THINK–PAIR–SHARE
1. What is the likelihood that hydrogen (H2) will become a widely used fuel and that the hydrogen economy
will become a reality? What are the advantages and disadvantages of H2 as a fuel? What would be
necessary for a significant conversion to a hydrogen economy?
Answer:
Hydrogen economy discussion:
For hydrogen to become a widely used fuel several infrastructure issues must be overcome. These
include economical hydrogen production facilities (presumably from water electrolysis), storage
facilities, and refueling stations. These are costly investments for a nation or corporation to make. If
the cost-benefit analysis swings in the direction of a hydrogen economy, then it becomes a possibility.
Until then, the odds are not good.
Hydrogen has the advantage that upon combustion it produces water and no greenhouse gases,
especially carbon dioxide. Hydrogen also is a good fuel producing more energy per gram than light
hydrocarbons. A major disadvantage is that present methods of producing hydrogen are fossil fuel
based. If water electrolysis becomes economically viable, that is probably the best option for an
environmentally friendly method of producing hydrogen.
For a significant conversion to a hydrogen economy there must be a realization that climate change is
sufficiently harmful to necessitate a switch from fossil fuels to more eco-friendly energy sources.
2. An understanding of most environmental issues requires one to consider a range of factors—economic,
political, sociological, and scientific. Discuss each of the issues below.
a. Fracking is now in wide use, allowing access to large quantities of natural gas. What are the
positive factors that argue for continued and expanded use of this technique, and what are the
concerns?
b. Most gasoline now sold contains ethanol. Is production of ethanol for use as a fuel a wise choice?
What are the arguments for and against this policy.
Answer:
Economic, political, sociological, and scientific issues to consider:
a. Fracking:
Fracking has proven to be an economically viable way to expand US fossil fuel resources. It is one
of the main reasons the US has become an energy supplier to the world rather than dependent on
energy imports.
Fracking requires extensive use of solvents to remove oil and gas from rock deposits. Some of
these solvents are not environmentally friendly, including hydrofluoric acid. Extensive fracking in
Oklahoma led to a series of earthquakes in a normally geologically quiet portion of the US.
Fracking is not as cheap a source of oil and gas as regular drilling.
b. Ethanol:
In the US ethanol to be used as a fuel is primarily produced from the fermentation of corn sugar.
On the surface it is a non-fossil fuel based energy source and a major consumer of millions of tons
of corn annually produced in the US. Many farmers and corporations in the US rely on selling
their corn to produce ethanol. It is a renewable resource that has a strong economic base.
From a thermodynamic perspective, the energy content of ethanol is about two-thirds that of
petroleum fuels. Furthermore, corn production is energy intensive. Fertilizers, tractor fuel, and
transportation, etc., consume more energy than ethanol fuel produces. Finally, when ethanol is
burned in automobile engines it produces the air pollutant peroxyacetyl nitrate a more powerful
oxidant than ozone.
© 2024 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly 2
accessible website, in whole or in part.
, Solution and Answer Guide: Kotz Treichel Townsend Treichel, Chemistry and Chemical Reactivity 11e, 978-0-357-85140-1,
Chapter 25: Environmental Chemistry—Earth’s Environment, Energy, and Sustainability
3. What are the environmental consequences of ozone in the troposphere? In the stratosphere?
Answer:
Environmental consequences of ozone:
In the troposphere: Ozone is an air pollutant in the troposphere where it can damage lungs and affect
plant life.
In the stratosphere: Stratospheric ozone is necessary for life as we know it to exist on Earth. At
altitudes of 25-30 km ozone interacts with ultraviolet (UV) radiation from the Sun reducing it to levels
that is not harmful to life. However, enough UV radiation still reaches the Earth’s surface to cause
sunburn.
4. Compare the advantages and disadvantages of the different methods used to disinfect drinking water.
Answer:
Advantages and disadvantages of different methods to disinfect drinking water:
Addition of oxidizing agents, such as chlorine and sodium hypochlorite, is effective and persistent.
Thus, water disinfected in this manner can remain in water pipes for extended periods of time and
remain safe. Addition of chlorine to water does produce small amounts of toxic trihalomethanes.
Ozonolysis is another good method to disinfect water. It must be done on site at the water plant with a
dedicated ozonolysis facility. The cost of ozonolysis is greater than the use of chlorine and sodium
hypochlorite. Water treated with ozone does not have residual disinfection in the treatment system.
Reverse osmosis is another method to purify water, especially seawater. Cost wise, reverse osmosis
has become compatible with other methods. This method is primarily used in countries that have few
natural water supplies but with access to seawater.
5. Carbon dioxide reacts to a small extent with water to produce carbonic acid (H2CO3). The figure illustrates
the fractional distributions (also known as alpha values) of H2CO3, HCO3−, and CO32− in an aqueous
solution as a function of pH.
a. If the pH of the solution is 2, which species would predominate?
b. What are the major species in solution at a pH of about 6.4, and what are their relative amounts?
c. At approximately what pH will equal concentrations of HCO3− and CO32− exist in the solution?
d. The normal pH of human blood is about 7.4. What is the dominant species in the aqueous CO2
system at this pH?
© 2024 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly 3
accessible website, in whole or in part.
Chemistry & Chemical
Reactivity 11th Edition By John
Kotz, Paul Treichel, John
Townsend, David Treichel (All
Chapters 1-25, 100% Original
Verified, A+ Grade)
All Chapters Arranged
Reverse: 25-1
Part 1: Instructor Solutions Manual
Part 2: Student Solutions Manual
, Solution and Answer Guide: Kotz Treichel Townsend Treichel, Chemistry and Chemical Reactivity 11e, 978-0-357-85140-1,
Chapter 25: Environmental Chemistry—Earth’s Environment, Energy, and Sustainability
Solution and Answer Guide
Kotz Treichel Townsend Treichel, Chemistry and Chemical Reactivity 11e, 978-0-357-85140-1,
Chapter 25: Environmental Chemistry—Earth’s Environment, Energy, and Sustainability
TABLE OF CONTENTS
Think–Pair–Share ....................................................................................................................................... 2
Part 1: Instructor Solutions Manual: Chapter 25-1
© 2024 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly 1
accessible website, in whole or in part.
, Solution and Answer Guide: Kotz Treichel Townsend Treichel, Chemistry and Chemical Reactivity 11e, 978-0-357-85140-1,
Chapter 25: Environmental Chemistry—Earth’s Environment, Energy, and Sustainability
THINK–PAIR–SHARE
1. What is the likelihood that hydrogen (H2) will become a widely used fuel and that the hydrogen economy
will become a reality? What are the advantages and disadvantages of H2 as a fuel? What would be
necessary for a significant conversion to a hydrogen economy?
Answer:
Hydrogen economy discussion:
For hydrogen to become a widely used fuel several infrastructure issues must be overcome. These
include economical hydrogen production facilities (presumably from water electrolysis), storage
facilities, and refueling stations. These are costly investments for a nation or corporation to make. If
the cost-benefit analysis swings in the direction of a hydrogen economy, then it becomes a possibility.
Until then, the odds are not good.
Hydrogen has the advantage that upon combustion it produces water and no greenhouse gases,
especially carbon dioxide. Hydrogen also is a good fuel producing more energy per gram than light
hydrocarbons. A major disadvantage is that present methods of producing hydrogen are fossil fuel
based. If water electrolysis becomes economically viable, that is probably the best option for an
environmentally friendly method of producing hydrogen.
For a significant conversion to a hydrogen economy there must be a realization that climate change is
sufficiently harmful to necessitate a switch from fossil fuels to more eco-friendly energy sources.
2. An understanding of most environmental issues requires one to consider a range of factors—economic,
political, sociological, and scientific. Discuss each of the issues below.
a. Fracking is now in wide use, allowing access to large quantities of natural gas. What are the
positive factors that argue for continued and expanded use of this technique, and what are the
concerns?
b. Most gasoline now sold contains ethanol. Is production of ethanol for use as a fuel a wise choice?
What are the arguments for and against this policy.
Answer:
Economic, political, sociological, and scientific issues to consider:
a. Fracking:
Fracking has proven to be an economically viable way to expand US fossil fuel resources. It is one
of the main reasons the US has become an energy supplier to the world rather than dependent on
energy imports.
Fracking requires extensive use of solvents to remove oil and gas from rock deposits. Some of
these solvents are not environmentally friendly, including hydrofluoric acid. Extensive fracking in
Oklahoma led to a series of earthquakes in a normally geologically quiet portion of the US.
Fracking is not as cheap a source of oil and gas as regular drilling.
b. Ethanol:
In the US ethanol to be used as a fuel is primarily produced from the fermentation of corn sugar.
On the surface it is a non-fossil fuel based energy source and a major consumer of millions of tons
of corn annually produced in the US. Many farmers and corporations in the US rely on selling
their corn to produce ethanol. It is a renewable resource that has a strong economic base.
From a thermodynamic perspective, the energy content of ethanol is about two-thirds that of
petroleum fuels. Furthermore, corn production is energy intensive. Fertilizers, tractor fuel, and
transportation, etc., consume more energy than ethanol fuel produces. Finally, when ethanol is
burned in automobile engines it produces the air pollutant peroxyacetyl nitrate a more powerful
oxidant than ozone.
© 2024 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly 2
accessible website, in whole or in part.
, Solution and Answer Guide: Kotz Treichel Townsend Treichel, Chemistry and Chemical Reactivity 11e, 978-0-357-85140-1,
Chapter 25: Environmental Chemistry—Earth’s Environment, Energy, and Sustainability
3. What are the environmental consequences of ozone in the troposphere? In the stratosphere?
Answer:
Environmental consequences of ozone:
In the troposphere: Ozone is an air pollutant in the troposphere where it can damage lungs and affect
plant life.
In the stratosphere: Stratospheric ozone is necessary for life as we know it to exist on Earth. At
altitudes of 25-30 km ozone interacts with ultraviolet (UV) radiation from the Sun reducing it to levels
that is not harmful to life. However, enough UV radiation still reaches the Earth’s surface to cause
sunburn.
4. Compare the advantages and disadvantages of the different methods used to disinfect drinking water.
Answer:
Advantages and disadvantages of different methods to disinfect drinking water:
Addition of oxidizing agents, such as chlorine and sodium hypochlorite, is effective and persistent.
Thus, water disinfected in this manner can remain in water pipes for extended periods of time and
remain safe. Addition of chlorine to water does produce small amounts of toxic trihalomethanes.
Ozonolysis is another good method to disinfect water. It must be done on site at the water plant with a
dedicated ozonolysis facility. The cost of ozonolysis is greater than the use of chlorine and sodium
hypochlorite. Water treated with ozone does not have residual disinfection in the treatment system.
Reverse osmosis is another method to purify water, especially seawater. Cost wise, reverse osmosis
has become compatible with other methods. This method is primarily used in countries that have few
natural water supplies but with access to seawater.
5. Carbon dioxide reacts to a small extent with water to produce carbonic acid (H2CO3). The figure illustrates
the fractional distributions (also known as alpha values) of H2CO3, HCO3−, and CO32− in an aqueous
solution as a function of pH.
a. If the pH of the solution is 2, which species would predominate?
b. What are the major species in solution at a pH of about 6.4, and what are their relative amounts?
c. At approximately what pH will equal concentrations of HCO3− and CO32− exist in the solution?
d. The normal pH of human blood is about 7.4. What is the dominant species in the aqueous CO2
system at this pH?
© 2024 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly 3
accessible website, in whole or in part.
