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SOLUTION MANUAL FOR CHEMISTRY IN CONTEXT 10TH EDITION AMERICAN CHEMICAL SOCIETY Chapter 1-14

ANSWERS TO END-OF-CHAPTER QUESTIONS CHAPTER 1: Portable Electronics: The Periodic Table in the Palm of Your Hand

Emphasizing Essentials 1. Answer: a. Compound (2 molecules of one compound made up of two different elements). b. Mixture (2 atoms of one element plus 2 atoms of another). c. Mixture (3 different substances, two elements and one compound). d. Element (4 atoms of the same element).

2. Answer: a. element (4 molecules of one diatomic element) b. Compound (2 molecules of one compound made up of two different elements). c. Mixture (2 atoms of one element plus 2 atoms of another). d. Compound (4 molecules of one compound made up of two different elements).

3. Answer: Exact answer will vary depending on viewing size of text. An approximate measurement for the period could be 0.25 mm. Converting this to nanometers: -

or 250,000 nm.

4. Answer: Converting 10.0 nanometers to millimeters:

5. Answer: a. 1.5  103 m b. 9.58  10–11 m c. 7.5  10–6 m

6. Answer:

7. Answer: a. Group 1 and Group 17 b. 1A: lithium, sodium, potassium, rubidium, cesium, francium 7A: fluorine, chlorine, bromine, iodine, astatine c. 1A: All but hydrogen (a nonmetal) are reactive metals. 7A: All but astatine (a metalloid) are reactive nonmetals.

8. Answer: a.

b. iron, Fe; magnesium, Mg; aluminum, Al; sodium, Na; potassium, K; silver, Ag. c.

d. sulfur, S; oxygen, O, carbon, C, chlorine, Cl, fluorine, F (and others).

9. Answer: a. compound d. element

b. compound e. mixture

c. mixture f. element

10. Answer: a. heterogenous mixture d. homogenous mixture

b. heterogenous mixture e. heterogenous mixture

c. heterogenous mixture

11. Answer:

Grey spheres: electrons Black spheres: protons White spheres: neutrons

12. Answer: There are several allotropes of sulfur. The most stable and common allotrope consists of 8 atoms in a ring. Other common allotropes include rings of 5, 6, 7, 10 and larger number of atoms. Most allotropes are yellow solids, although they can be found in liquid or gaseous forms at appropriate temperatures. Most of these allotropes are created by heating sulfur of the 8-membered ring form.

13. Answer: An aluminum atom with mass number 27 has 13 protons, 14 neutrons, and 13 electrons.

14. Answer: A copper atom with a mass number 64 has 29 protons, 35 neutrons, and 29 electrons. 15. Answer: Electrical conductivity is the transport of electrons from one location to another. Thermal conductivity is the transfer of heat from one location to another. Their difference is in what is being transferred. 16. Answer: a. t t

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17. Answer: a. 1 carbon atom (nonmetal), 2 oxygen atoms (nonmetals) b. 2 hydrogen atoms (nonmetals), 1 sulfur atom (nonmetal) c. 1 nitrogen atom (nonmetal), 2 oxygen atoms (nonmetals) d. 1 silicon atom (metalloid), 2 oxygen atoms (nonmetals)

Concentrating on Concepts 18. Answer: A variety of answers are possible. An example of an illustration of 9N purity is the time span of 1 second compared to 31.7 years. A similar example with 12 N purity is 1 second compared to 31,700 years. A volume-related example of 9N purity would be like taking 1 liter of water out of 400 Olympic-sized swimming pools full of water!

19. Answer: Answers will vary widely but could include food, drink, furniture, books, and appliances, among others. Examples of homogeneous mixtures may be air (nitrogen, N2, oxygen, O2, argon, Ar, etc.), Gatorade (water, H2O, sucrose, C12H22O11, sodium chloride, NaCl, citric acid, C6H8O7, etc.), and glass (silicon dioxide, SiO2, sodium oxide, Na2O, calcium oxide, CaO, aluminum oxide, Al2O3, Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

etc.). Examples of heterogeneous mixtures include books (cellulose, (C6H10O5)n, carbon black, C, titanium oxide, TiO2, polyvinyl acetate, (C4H6O2)n, etc.), granola bar (sucrose, C12H22O11, sodium chloride, NaCl, baking soda, NaHCO3, etc.), and a banana (water, H2O, glucose, C6H12O6, fructose, C6H12O6, isoamyl acetate, C7H14O2, etc.)

20. Answer: Answers will vary, depending on year selected. As of 2019, the latest technology node is 5 nm, which features a gate length of around 10 nm (https://en.wikichip.org/wiki/5_nm_lithography_process). -

This is equivalent to

21. Answer: The periodic table allowed gaps for unknown elements. The elements were placed into gaps based on their atomic weight and number of protons. 22. Answer: There are many steps involved during this process. Many resources are available on the Internet that describe this process (e.g., http://www.australianminesatlas.gov.au/education/fact_sheets/aluminium.html) 23. Answer: Sapphire is about three times as hard as Gorilla glass but is about 67% more dense. This means that although sapphire could greater resist scratches, a similar sized piece would weigh more than a piece of Gorilla glass. Gorilla glass has an amorphous structure composed primarily of silicon and oxygen atoms with other minority component atoms. Sapphire is a single crystal of aluminum and oxygen atoms. Both materials require high temperature melting of raw materials followed by slow cooling. Gorilla glass requires another heating step in a molten bath of salts. Sapphire requires a much higher temperature melt. Regular glass is also amorphous & is composed primarily of silicon and oxygen atoms with additives of sodium and calcium oxides. A comprehensive website that quantitatively compares the physical and optical properties of typical soda-lime glass, Gorilla glass, and quartz is found at: http://abrisatechnologies.com/specs/AT%20Specialty%20Glass%20Technical%20Capabilities%2 0Brochure.pdf

24. Answer: A thin layer of a transparent conducting material is deposited on the surface of glass. The most common material used for this purpose is indium tin oxide (ITO), which is used in applications ranging from LED displays to solar cells. Do-it-yourself enthusiasts have posted to the internet a way to coat glass using stannous chloride (SnCl2) to create a layer of conductive tin oxide.

25. Answer: Wh th sur ss s qu y Pr Rup rt‘s dr p, s d xy t s r tight bonds that hold the material into shape. The silicon and oxygen atoms within the drop are still semi-mobile while the outer surface is hardening. When the interior of the drop cools, new bonds between silicon and oxygen form, pulling them tighter together. However, since the other layer of glass is held tightly in place, the atoms on the interior are not able to approach each other as close as optimal, resulting in internal stress. When some of the bonds between silicon and oxygen atoms in the surface of the glass are broken, the internal bonds are pulled tightly together with enough strength to further break additional bonds in the outer layer. This results in the shattering of the drop as bonds throughout the glass break or shrink. 26. Answer: Answers will vary depending on device and component choice, but typical components and sizes include length (e.g. 14.5 cm, 145 mm, 145,000 µm, 145,000,000 nm); width (e.g. 7.5 cm, 75 mm, 75,000 µm, 75,000,000 nm); thickness (e.g. 1 cm, 10 mm, 10,000 µm, 10,000,000 nm); camera lens (e.g. 0.3 cm, 3 mm, 3,000 µm, 3,000,000 nm); and speaker hole diameter (e.g. 0.03 cm, 0.3 mm, 300 µm, 300,000 nm). 27. Answer: h st t s us d ph s th t r E rth‘s rust ud s: u u , r potassium, magnesium, titanium, manganese, barium, and nickel. They are found in ores, minerals, and compounds.

28. Answer: A transparent material allows light to travel through it without refracting. Having a transparent screen keeps the light produced from distorting when you look at it. Additives can give solids like glass a different color or other properties like strength. Heat treatment can also add durability. 29. Answer: Gold prospectors can use panning to separate gold flakes from other solids. This involves taking the mixture and agitating it in water. This separates out the gold because it stays in the bottom of the pan and other substances float in the water and can be poured out. 30. Answer: The steps involved to convert silica sand, mostly composed of SiO2, to high-purity Si are outlined in Section 1.8. In contrast, sea sand contains many impurities such as metals (e.g., Fe, Al, Mg, K, Na, Ca, Zn, Ni, etc.) and nonmetals (e.g., B, P) that would require extensive pre-processing of the sand via chemical reactions, involving acids and high temperatures. Furthermore, the use of sea sand for industrial processes would not be sustainable and would cause a variety of environmental consequences. By disturbing sea sand, an area could be changed physically, biologically, and chemically.

31. Answer: Waste products of high-purity silicon include carbon monoxide (from reduction of the silicon), carbon dioxide (from combustion heating), compounds containing the impurities (including phosphorous, boron, and a variety of metals), and waste heat. Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

32. Answer: While individual cell phones may become smaller and take up less space in, say, a landfill, there may be a much higher impact on the environment, depending on the materials required for making the cell phone and the energy needed for manufacturing the components. To make the devices smaller and less expensive, different materials may be used, which may require more invasive mining or greater waste production in the manufacturing process. 33. Answer: A sw rs w v ry rd t r tv w h t rs h r d r th ―E v r t ‖ pillar should consider the production and recycling of waste and the relative use of limited natural r s ur s, ud r r rth t s h r d r th ― ‖ p r sh u d ud b th th impact of portable electronics on the quality of life of consumers as well as the impact on the lives of workers in the mining of raw materials, manufacturing of the products, and those that live th r s p t d by d u tur h r d r ―E ‖ p r sh u d consider the wealth generated by the mining, manufacturing, and sale of these electronics and how this wealth is distributed.

Exploring Extensions 34. Answer: Gordon Moore, one of the founders of the computer chip maker Intel, predicted in 1965 that the number of transistors per square inch on integrated circuits would double every 12 months. In 1975, he revised his prediction to double every 24 months. This prediction has held true through at least 2016. However, both Moore and current Intel CEO Brian Krzanich have recently suggested that chip makers may reach physical and economic limitations to this growth within the next 5-10 years. 35. Answer: The colors of many gemstones come from impurities in the crystal structure. For example, the purple color of amethyst comes from Fe3+ ions in a SiO2 crystal, and the red color of rubies comes from Cr3+ in an Al2O3 crystal.

36. Answer: Impurities break up the crystal structure of crystalline solids and, since properties of materials are in part dependent on structure, this will change the material properties. Throughout this chapter, we have seen impurities that change properties such as color, transparency, melting point, and electrical conductivity.

37. Answer: A thin layer of material is sandwiched between two pieces of glass. When an electrical current is passed through the glass, the material will line up according to the direction of the current, similar the liquid crystal display (LCD) of common calculators.

Devices can be physically pulled apart to reveal the components containing the metals. Plastic parts such as circuit boards are either dissolved in solvent or burned to isolate the metallic components. These metals themselves may be either melted or dissolved in acids and then filtered and reconstituted to generate purer forms of the metal for other uses. A recent report describes the use of fungi to extract precious metals from electronic waste, a potentially more environmentally friendly way of recycling.

39. Answer: Apple has removed mercury and arsenic from screens and lead from solder in their electronics.

40. Answer: The two largest destinations for electronic waste in the world are in New Dehli, India, and Guiyu, China. Studies have shown air, water, and soil pollution from electronics recycling around Guiyu leading to poisoning from heavy metals such as lead and organic pollutants such as dioxins. To prevent these situations, new methods of recycling need to be developed with greater safety awareness for workers, tighter controls on emissions from recycling centers, and redesign of the electronic devices to reduce toxic components.

41. Answer: Old electronic devices could be disassembled and either parts could be reused as is or could be mechanically or chemically separated into raw materials to be used for manufacturing new devices.

42. Answer:

The H2 and SiCl4 gases are recycled through reaction to generate chlorosilanes that are used to purify the Si in earlier steps. However, CO is released, which is further oxidized to CO2, a greenhouse gas. 43. Answer: Answers will vary as there are many ways to strengthen glass. This may include heating the glass or adding different elements into the structure.

44. Answer: There were 46.89 million iPhones sold in 2018. 25% of this is 11.72 million. An iPhone 8 has a mass of 202 grams. 24% of the mass of an iPhone is Al, so one phone has 48.48 grams. This multiplied by 11.72 million iPhones is kg. Copper is 6% of the mass of an iPhone, which is 12.12 grams per iPhone. This multiplied by 11.72 million iPhones is kg. Cobalt is 5% of the mass of an iPhone, which is 10.1 grams per iPhone. This multiplied by 11.72 million iPhones is kg. Each iPhone contains 300 mg of silver, multiplied by 11.72 million is 3516 kg of silver. Each iPhone contains 30 mg of gold, multiplied by 11.72 million is 351.6 kg. At current pricing, this yields: Al: $1,949,376, Cu: $862,224, Co: $4,062,740, Ag: $1,913,196, Au: $16,598,779=$25,386,315. 45. Answer: refer back to Figure 1.24. A cradle-to-cradle scenario would include recycling of metals, plastics, etc. in the phone back into a useful end product.

46. Answer: Some considerations include toxicity of materials used in the device, availability of raw materials, amount of energy required by the device, and number of uses for the device and disposable components (such as batteries).

47. Answer: To extract aluminum from ore, bauxite is crushed and dissolved in a solution of concentrated sodium hydroxide to remove aluminum oxide from the rest of the ore. The aluminum oxidesodium hydroxide mixture is then neutralized and is mixed with sodium aluminum fluoride (cryolite). At high temperatures, a carbon electrode is used to reduce the aluminum oxide to molten aluminum. This process is very energy intensive and expensive. Aluminum recycling involves collecting used aluminum, cleaning the metal, then melting the metal to remove any coating, and then cooling the metal to form solid aluminum. The recycling process uses high temperatures to melt the metal, but uses much less energy and is more cost efficient than extraction. Recycling uses more than 90 percent less energy than extraction from bauxite.

48. Answer: The increase in demand for rare earth metals amounts to about 40%. Rare earth metals are used in a wide variety of products such as cell phones, computers, rechargeable batteries, wind turbines, speakers, and fluorescent lights. It is doubtful that the U.S. could meet its demand for rare earth elements even with 100% recovery of the metals. The growth of the market for this wide variety of products outpaces the retirement of old products, many of which may not use much if any rare earth metals that could be recycled.

ANSWERS TO END-OF-CHAPTER QUESTIONS

CHAPTER 2: THE AIR WE BREATHE

Emphasizing Essentials 1. Answer: a.

0.5 L 10 breaths 60 min   7.5 hr  2.,250 L 1 breath 1 min 1 hr

b. Possibilities include burning less (wood, vegetation, cooking fuels, gasoline, incense), using products that pollute less (low-emission paints), and using motor-less appliances and tools (hand lawnmower, egg- beater, broom, rake)

2. Answer: a. Rn < CO < CO2 < Ar < O2 < N2 b. CO and CO2 c. CO. With concerns growing over climate change, By the time this book is in print, CO2 may be regulatedis also becoming regulated in terms of carbon taxes and other policies in some countries. as well. d. Rn (radon) and Ar (argon)

3. Answer: Examples of particulate matter found in air include dust, soot, dirt, microscopic droplets of liquid, bacteria, and viruses. PM2.5 and PM10 d r s z h r r h s p rt s μ r ss diameter; the latter 10 μ r ss h s r p rt s r r d t hu h th

4. Answer: a.

0.934 parts per hundred 

1,000,000 parts per million  9340 parts per million 100 parts per hundred

(Move the decimal 4 places to the right.)

100 partsper hundred 2 ppm 0.0002 partsper hundredor 0.0002% 1,000,000ppm (Move the decimal 4 places to the left.) 20 ppm is equivalent to 0.0020%. 50 ppm is equivalent to 0.0050%.

100 parts per hundred 8,500 ppm  0.85 parts per hundred or 0.85% 1,000,000 ppm

Be careful not to confuse the absolute humidity calculated in this problem with relative humidity, which is the amount of water vapor in the air compared to the maximum possible amount of water vapor that the air can hold at a particular temperature. For example, in a rainforest, the relative humidity is usually between 75- and 95%.

d. 8 ppm is 0.0008% (move the decimal 4 places to the left).

5. Answer: a. The chemical formula tells the elements present in a compound and the atomic ratio of the elements. b. Xe (xenon), N2O (dinitrogen oxide or nitrous oxide), CH4 (methane) Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

6. Answer: a. Hydrocarbons are compounds that contain only the elements hydrogen and carbon. b. ethane (C2H6), propane (C3H8), pentane (C5H12), hexane (C6H14), octane (C8H18) c. Answers will vary.Hydrocarbons release energy when they undergo combustion.

7. Answer: The majority of our air is composed of nitrogen, oxygen, and water, argon, but the air is made up of other molecules such as in very small concentrations (on the order of a few1 molecules perin 100 or less). Examples of a trace substances found in air will vary, but the molecule responsible for the fragrance of a flower or fresh baking cookies are examples. Other gases such as the inert gases or carbon dioxide could also be considered trace substances. It should be noted that even though a gas may be present in trace amounts (e.g., CO2, CO, O3), it may have significant implications for pollution or climate change.

8. Answer: Nitrogen is 78.0% of the air, meaning that out of 100 air particles, 78 of them are nitrogen molecules.

500 air particles 

78 nitrogen molecules 390 nitrogen molecules 100 air particles

Oxygen is 21.0% of the air, meaning that out of 100 air particles, 21 of them are oxygen molecules.

500 air particles 

21 oxygen molecules 105 oxygen molecules 100 air particles

Argon is 0.9% of the air, meaning that out of 100 air particles, 0.9 of them are argon atoms.

(

500 air particles 

)

0.9 argon atoms  4.5 argon atoms (or between 4 - 5 argon atoms) 100 air particles

9. Answer: a. Each side of the equation has 6 C, 16 H, and 14 O. b. Each side of the equation has 16 C, 36 H, and 50 O.

10. Answer: a. Yes, the mass of the reactants equals the mass of the products. The lLaw of cConservation of matter and mMass applies. b. No, the numbers of molecules are not the same (four reactant molecules vs. two product molecules). c. Yes, the numbers of each type of atom present as reactants and products are the same.

11. Answer: a. N2(g) + O2(g)  2 NO(g) (occurs at high temperature) b. O3(g)  O2(g) + O(g) (occurs in the presence of UV light) c. 2 S(s) + 3 O2(g)  2 SO3(g)

12. Answer: a. C3H8(g)  5 O2(g)  3 CO2(g)  4 H2O(g) b. 2 C4H10(g)  13 O2(g)  8 CO2(g)  10 H2O(g) c. 2 C3H8(g)  7 O2(g)  6 CO(g)  8 H2O(g) 2 C4H10(g)  9 O2(g)  8 CO(g)  10 H2O(g)

13. Answer: a. 2 C2H6(g) + 3 O2(g)  4 C(s) + 6 H2O(g) b. 2 C2H6(g) + 5 O2(g)  4 CO(g) + 6 H2O(g) c. 2 C2H6(g) + 7 O2(g)  4 CO2(g) + 6 H2O(g) Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

d. The balanced equations show that complete combustion requires the highest ratio of oxygen to ethane (7:2). If a 5:2 ratio is present, carbon monoxide is formed instead of carbon dioxide. If only a 3:2 ratio is available, then carbon (soot and particulate matter) is formed. Note: With less oxygen, the products are likely to be mixed, rather than pure CO or pure soot.

14. Answer: A homogenous mixture is a substance composed of many different components that are mixed well, like the air we breathe. Examples will vary, but one homogenous mixture is lemonadea solution of salt water. It is made by stirring together lemon juice, sugar, and watersalt and water together. Another example is sand from the beach. If you look closely, it is made up of a variety of different chemical components in addition to seaweed, shells, etc. vinegar which is acetic acid mixed with water.

15. Answer: In respiration, inhaled oxygen reacts with sugar in your body to produce carbon dioxide and water vapor to produce energy. Therefore, exhaled air has a decreased percentage of oxygen, and increased percentage of carbon dioxide. Oxygen is used to metabolize the food that we eat.

16. Answer: The troposphere is the layer of air closest to earth, the place where we live. It contains 75% of the air we breathe, by mass, and is where air currents and storms occur that mix the air in our atmosphere.

17. Answer: Symbolic = CO2

Macroscopic =

18. Answer: NO2 = nitrogen dioxide N2O = dinitrogen monoxide NO = nitrogen monoxide NCl = nitrogen trichloride N2O4 = dinitrogen tetraoxide

19. Answer:

CCl4 = carbon tetrachloride SO3 = sulfur trioxide Cl2O6 = dichlorine hexaoxide P4S3 = tetra phosphorus trisulfide

20. Answer: a.

400 parts per million 

100 parts per hundred  0.04 parts per humdred  4% 1,000,000 parts per million

b. Carbon monoxide is an air pollutant because when breathed into the lungs, CO can be hazardous to human health.

c. Carbon monoxide interferes with the ability of hemoglobin to carry oxygen throughout your body. If you are exposed to CO in high enough concentrations, it can cause a person to die due to lack of oxygen. Shorter term exposure leads to dizziness or a headache.

21. Answer: a. You will most likely find sulfur dioxide and nitrogen dioxide close to their sources (i.e., coal fired power plants and automobiles), around cities in the troposphere, although they can travel on air currents to other parts of the world.

b. Sulfur dioxide is more toxic. The U.S. Ambient Air Quality Standards sets a limit of 0.075 ppm for a one-hour exposure, as opposed to nitrogen dioxide at 0.100 ppm for a one-hour exposure. c.

0.045 parts per million 

1,000,000, 000 parts per billion  45 parts per billion 1,000,000 parts per million

22. Answer:

Concentrating on Concepts

2322. Answer:

The Hydra photograph shows sea walls, presumably built by humans (requiring fuel to be burned in the process of moving the stones). If the stones are cemented, the cement also will emit gases as it dries. The ships are giving off emissions from the burning of fuel. The restaurant might be emitting the good smells of fresh Greek food.

The Tianjin photograph is easier. The cars and buses on the road leave air prints as they burn fuel. Any spilled fuel may evaporate into the air. The haze is most likely the result of emissions from vehicles and industry nearby.

2423. Answer: Carbon monoxide: Mild CO poisoning makes you feel crummy, including headache, dizziness, and nausea. You will not be able to exert yourself in your normal manner. More severe poisoning may send you unconscious to the emergency room. Particulate matter: Mild PM poisoning will cause lung and cardiovascular distress. Again, you will not feel up to things with your normal energy level. More severe poisoning can send you to the emergency room with a heart attack. Ozone: Mild ozone poisoning will cause your eyes and throat to burn. It will aggravate your breathing and asthma. As with CO and PM, more severe ozone poisoning can send you to the emergency room.

Answers will vary depending on the answer calculated in Your Turn 2.2 and the size of the classroom. For most students, the volume of air inhaled in a day will be on the order of 10,000 L. The classroom length, width, and height measurements can be estimated in meters. One cubic meter equals 1,000 liters, so classrooms should hold a much greater volume of air than a student exhales in a day.

2625. Answer: In respiration, inhaled oxygen reacts with substances in your body to produce carbon dioxide and water vapor. Therefore, exhaled air has a decreased percentage of oxygen, and increased percentage of carbon dioxide.

2726. Answer: a. Normally, the exhaust gases are released to the atmosphere through the tailpipe and do not find their way back into the interior of the car. The tailpipe does not have a connection to the interior. However, if the gases are released into an enclosed space like a snow bank, they may seep back into the car as there is no easy escape path into the wider environment. b. CO is an odorless, colorless, and tasteless gas. 2827. Answer: Here are some possibilities: - Iron and steel would rust more slowly, prolonging the useful life of many objects made from these materials. - Fires would burn less vigorously and produce more CO and soot. Logs in your fireplace might last longer, putting out heat more slowly. - Your body can adapt (just as it does at higher elevations) to lower levels of oxygen. But in this case, the level may be too low for metabolic processes involving oxygen to occur at fast enough rates for life as we currently know it.

2928.

Answer:

O s t r d th ―s t r‖ b us y ur s s s t d t t th s r ss, t st ss, d odorless gas. The same term cannot be applied to pollutants such as O3 or SO2 because each has a distinctive odor that can be detected at concentrations below the level of toxicity.

3029. Answer: a. To convert from percent to ppm, move the decimal point 4 places to the right. Alternatively:

3% = 3 pph 1,000,000 ppm 3 pph   30,000 ppm 100 pph



3pph

1,000,000 ,000 ppb  30,000,000 ppb 100 pph

b. The NAAQS for CO in an 8-hour period is 9 ppm. The concentration of CO in cigarette smoke is over three thousand times the 8-hour standard. The NAAS for CO in a 1-hour period is 35 ppm. The concentration in cigarette smoke is almost nine hundred times the 1-hour standard. c. Smokers do not die from CO poisoning because they breathe mainly air, not pure cigarette smoke.

3130. Answer: The ozone levels are not reported in the winter because of the differences in the sunlight between the summer and the winter. Even at its greatest winter intensity, the sunlight is much less intense. Sunlight is needed to produce ozone.

3231. Answer: Reporting the absolute difference, 0.01 ppm, seems to minimize the amount by which the standard is exceeded, at least in the eyes of the general public. Unless the standard is reported as well, there is no way to compare the magnitude of the difference to the magnitude of the standard. Calculating the Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

percentage by comparing the difference (0.01 ppm) to the standard (0.12 ppm) gives 8%, which may give people a better understanding of the amount by which the standard was exceeded.

3332.Answer: a. The elderly, the young, and people with respiratory diseases such as asthma and emphysema are most affected by ozone. b. 3 days c. Ozone is highly reactive, thus does not persist long in the atmosphere. Since no ozone is produced t ht wh th su s ‘t shining, its concentration falls. d. Answers will vary. Possibilities include: overcast skies, rain, or high winds. It could be a day when fewer people are driving or that industries are shut down. e. Ozone levels in Atlanta, Georgia, are lower in December because there is less daylight in the winter months.

3433. Answer: a. The elderly, the young, and people with respiratory diseases such as asthma and emphysema are most affected by PM. b. December 21-22, December 27, December 31 c. Although PM varies in composition, most of it is less chemically reactive than ozone. It typically is removed from the air by rain or wind. d. Possibilities include smoke blowing in from a wildfire outside the city, an air inversion, large industrial releases of soot, and a volcanic eruption somewhere in the region that released ash and soot.

3534. Answer: a. 15 ppm is 0.0015% and 2% is 20,000 ppm. 15 ppm is roughly 1300 times smaller than 20,000. b. c.

2 C12H26 (l)  37 O2(g)  24 CO2(g)  26 H2O(g)

d. Ultimately, burning diesel which is derived from the fossil fuel petroleum is not sustainable. In the short term, diesel engines also are old and have high emissions. So these have a high cost in terms of public health. However, the ultra-low sulfur diesel fuel is definitely a step in the right direction.

a. These regions have high population densities, high levels of vehicle emissions, possibly stagnant air, and lots of sunlight. Factors such as these lead to ozone formation. b. Possibilities include that it is overcast and/or raining in the Midwest. c. In the Sacramento Valley, air may become trapped such that air pollutants accumulate. Furthermore, the temperatures are higher and the days are sunnier, promoting ozone formation. In contrast, the air near the coastline has better circulation, which promotes better air quality. The air also is cooler and sometimes foggy.

3736. Answer: If you live in the U.S., check http://www.stateoftheair.org/, the State of the Air. You can easily count the ozone days in different states. You will find that the sunnier states in the south and southwest have higher levels of ozone beginning earlier in the year than those in the north.

3837. Answer: a. Reducing the number of cars in use will directly and indirectly reduce the concentrations of NOx, SOx, CO, CO2 and ozone in the air. b. Geographical features that lead to stagnant air, such as being situated in a valley or surrounded by mountains, may contribute to the higher ozone levels.

3938. Answer: CO is a hazard when present at the part per million level, and instruments can easily detect CO at this concentration. In contrast, radon levels are much lower, on the order of parts per 1020. Most radon detection kits sample the air over a period of time in order to get a high enough reading.

4039. Answer: a. h b u d r d ―L w VO p ts r du xp sur d r s s ss t d w th th s u s ‖

y ur xp sur t p

t u

b. VOCs are a player in the formation of NO2 from NO. In turn, NO2 breaks down in sunlight to produce O atoms that react with O2 molecules to produce ozone in the troposphere.

4140. Answer: a. Jogging outdoors, as opposed to sitting outdoors, increases your exposure to air pollutants because you will be breathing harder and exchanging more air during your exercise. b. Jogging indoors reduces your exposure to ozone (the O3 molecule is highly reactive and decomposes during the time it takes to transport the air inside). In contrast, particulate matter has Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

comparable levels inside and out (PM does not get filtered out by most air-handling equipment and it is not highly reactive). Some pollutants may be found at higher levels inside, such as the CO produced by faulty appliances.

4241. Answer: One possibility is to examine how you (and your clients, if you have them) use energy over the course of a day (heating, lighting, computing time, traveling). Reductions in energy use translate into improved air quality. This is true even for renewable energy sources such as solar and wind, because it still requires energy to manufacture and maintain the solar cells and wind turbines. Another possibility is to seek the connections between your work and air quality. For example, if you are in a medical profession, you could start better educating the public as to the health issues associated with breathing dirty air.

Exploring Extensions

42. Answer:

6 m  5 m  3 m = 90 m3 3600 mg acetone 

1000 g 1 g   40,000 3 3 1 mg 90 m m

43. Answer:



This phrase refers to what can happen when individuals use a natural resource (e.g., air we breathe, water we drink) that is shared by all for their own interests and then lower the quality of this resource, which is not in the best interest of a larger group of people. Air pollution is a classic example in that people add waste to the air which in turn affects the health and well-being of others. A case in point would be an industry (group of people) that burns coal to produce electricity. In the process of doing this, oxides of nitrogen and sulfide are released into the air. Other waste products include mercury and the greenhouse gas carbon dioxide. Clearly some people benefit, perhaps even those using the electricity. But all breathe the dirty air. Depending on the concentrations of pollutants, some people may sicken or die.

44. Answer: Fossil fuels contain trace amounts of mercury. When these fuels are burned, the mercury is released into the air. Forest fires and volcanoes are natural sources of mercury air pollution. However, mercury concentrations in the air are usually low and of little direct health concern. When air-borne Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

mercury enters water systems, biological processes transform it to a chemical form (methylmercury, or (CH3Hg)+) that can accumulate in fish and animals that eat fish. Organisms high in the food chain, such as fish, have the highest levels of mercury. People are exposed to mercury primarily by eating fish. A person’s level of mercury exposure can be measured by testing the amount of mercury in their blood. High mercury levels can cause neurological damage and are particularly harmful to fetuses, infants, and young children.

45. Answer: Visit the EPA website through http://www.epa.gov. The Green Chemistry website can be found at https://www.epa.gov/greenchemistry. http://www.epa.gov/greenchemistry. The Presidential Green Chemistry Challenge was established by President Bill Clinton in 1995 to promote pollution prevention and industrial ecology in partnership with the chemical industry.

46. Answer: a. The rubber may have come from tires abrading as they roll along the highways. Other sources of PM include soot from incomplete combustion and dirt picked up and blown by the wind. b. Iron, aluminum, and calcium also are commonly present. Other possibilities include sodium, potassium, magnesium, and sulfur. c. The edges of the particles appear to be irregular and jagged, thus likely to cause inflammation.

47. Answer: The American Lung Association website is a good place to start. Particulate matter comes from a variety of sources and can be solids or fine suspensions (aerosols) of liquids. Ultrafine particles can penetrate the lungs more deeply than coarser particles and thus are more likely to enter the bloodstream. Once in blood vessels, these fine particles inflame cells and tissues, leading to cardiovascular disease.

48. Answer: a. This graph clearly indicates that exposure to higher carbon monoxide concentrations over longer time periods becomes increasingly life-threatening. b. CO poses a serious health threat. This gas is colorless and odorless, making it impossible to detect without a monitor or kit. Furthermore, the initial symptoms of carbon monoxide poisoning are not unique, and those suffering from the associated headaches and nausea could easily presume the symptoms are due to a flu-like illness. Untreated, individuals will ultimately lapse into a coma, after Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

which point they will be unable to call for assistance. For these reasons such as these, carbon monoxide detectors are life-saving devices.

49. Answer: A water-based polyurethane was produced by removing the VOCs from the varnish and replacing them with water. As the source below reports: ― h s y s bv us subst tut , but, du t the particular chemistry of the reactive components of polyurethane, it is not that straightforward. The details are given here: https://www.epa.gov/greenchemistry/presidential-green-chemistry-challenge-2000-greenerreaction-conditions-award Several paint manufacturers currently market water-based polyurethanes. An internet search will quickly bring up examples.

50. Answer: The health hazards associated with isocyanate include irritation of the mucous membrane and skin, tightness in the chest, and difficulty breathing. Isocyanate is also a potential carcinogen for humans and is known to cause cancer in animals. a. Instead of using non-renewable, petroleum- based feedstocks to create adhesives, p s t s, d s, Pr ss r W ‘s pr ss s us dst s r b -based sources. These renewable sources include flax, chicken feathers, and vegetable oils. In addition to being renewable, their production uses less water and energy and is not as toxic as the petroleum- based counterparts. b. Answers will vary. Richard Wool passed away in 2015 and his work can be summarized here: http://www1.udel.edu/udaily/2015/apr/in-memoriam-wool-040615.html and here: https://www.researchgate.net/scientific-contributions/2077713776_Richard_P_Wool. 51. Answer:

a) Benzene studies have been conducted, but they were conducted on cars that are stuck in traffic. These levels are due mainly to exhaust. The values are also much lower than the viral post suggests. Parked cars that are not running but are found in direct sunlight can have trace amounts of VOCs but they are low amounts. More information can be found at: (1) https://www.liveabout.com/is-there-toxic-benzene-in-parked-cars-3298894 (2) https://pubs.acs.org/doi/full/10.1021/es0617901 (3) https://www.livescience.com/7273-car-smell-toxic-study-finds.html (4) https://emergency.cdc.gov/agent/benzene/basics/facts.asp (5) https://www.ncbi.nlm.nih.gov/pubmed/10412670 (6) https://www.sciencedirect.com/science/article/abs/pii/S0378427405001876 Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.

b) The new car smell is due to a combination of VOCs, including ethylbenzene, formaldehyde, toluene, etc. In excess, these chemical are harmful; however,, but in the amounts found in new cars, the studies do not show that harm is caused. One example of an article is here: https://cars.usnews.com/cars-trucks/best-cars-blog/2016/09/is-that-new-car-smell-toxic.

ANSWERS TO END-OF-CHAPTER QUESTIONS

CHAPTER 3: Radiation from the Sun

Emphasizing Essentials

1. Answer: The chemical formulas of ozone and oxygen are O3 and O2, respectively. Both are gases, but they differ in their properties. Oxygen has no odor; ozone has a very sharp odor. Although both are reactive, ozone is much more highly so. Oxygen is necessary for many forms of life; in contrast, ozone is a harmful air pollutant in the troposphere. However, ozone in the stratosphere helps to protect us from the harmful ultraviolet rays of the sun.

2. Answer: a. Yes, this is over the detection minimum of 10 ppb.

0.118 parts O3 118 parts O3 or 118 ppb  1,000, 000 parts air 1,000, 000, 000 parts air

b. Yes, this is well over the detection minimum of 10 ppb.



25 parts O3 25,000 parts O3 or 25,000 ppb  1,000, 000 parts air 1,000, 000, 000 parts air

 3. Answer: a h sz th km2 in area.

―h

‖v r s

h y r, but h s b

t dt b

s r



10 miles 

Yes, th surface.

km = 16.1 km 0.621 miles

ur s

rr t, s th str t sph r

xt ds b tw

b v th E rth‘s

c. Ozone absorbs UV-B and UV-C radiation.

4. Answer: The term ozone layer, while in widespread use, brings to mind an incorrect image of a blanket-like y r I t, v th str t sph r r h h st tr t , z ‘s tr t s typically less than 1 ppm and is not even the most abundant species in that region. The ozone does not completely block all UV radiation, such as a blanket might block all visible light. The ozone that is present, however, serves the essential function of absorbing some wavelengths of UV-B and reducing its intensity before it reaches the surface of the Earth, making the screen analogy more useful.

5. Answer: The air in the troposphere is simply denser than the stratosphere; the number of atoms and compounds in a given volume will be far higher. Also, the troposphere has a lower concentration of the gases like oxygen and ozone than the stratosphere. These gases are formed in the stratosphere and too reactive to mix downward. The opposite is also true, many gases formed in the troposphere, such as the NOxNOX or SOxSOX described in Chapter 2, are not common in the stratosphere.

6. Answer: a. The Dobson unit (or DU) measures the ozone in a column above a specific location on Earth. If this ozone were compressed at specified conditions of temperature and pressure, it would form a layer. A layer 3 mm thick corresponds to 300 DU. Similarly, a 1 mm layer corresponds to 100 DU. b. 320 DU > 275 DU. Thus, 320 DU indicates more total ozone overhead.

7. Answer: a. A neutral atom of oxygen has 8 protons and 8 electrons6 valence electrons. b. A neutral atom of nitrogen has 5 valence electrons7 protons and 7 electrons. c. A neutral atom of magnesium has 12 protons and 12 electrons2 valence electrons. However, it should be noted that magnesium forms ionic compounds rather than covalent, in which electrons are not shared. Copyright © 2017 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education.