AP Environmental Science : Greenhouse Gases

Study concepts, example questions & explanations for AP Environmental Science

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Example Questions

Example Question #1 : Greenhouse Gases

What is the primary source of the greenhouse gas Nitrous Oxide ()?

Possible Answers:

Livestock feedlots and synthetic fertilizers

Wood-burning stoves

Halocarbon gases

Natural gas

Deforestation

Correct answer:

Livestock feedlots and synthetic fertilizers

Explanation:

Chemical fertilizers are produced to fix nitrogen for farmers' fields, and while fields naturally lose nitrogen to the atmosphere in the form of , increased abundance of fixed nitrogen results in more  being released. Feedlots produce large quantities of nitrogen-rich animal waste, which also decays and enters the atmosphere in massive quantities.

Example Question #2 : Greenhouse Gases

The most abundant greenhouse gas in the Earth's atmosphere is __________.

Possible Answers:

water vapor

hydrogen

aerosols

ozone

chlorofluorocarbons (CFC's)

Correct answer:

water vapor

Explanation:

Water vapor is the most abundant greenhouse gas in the Earth's atmosphere. Infrared radiation that gets absorbed and reflected by the Earth's surface gets trapped and reflected back to the Earth's surface by greenhouse gasses in the atmosphere in a process known as the "greenhouse effect."

Example Question #1 : Greenhouse Gases

Which of the following greenhouse gasses is produced only by anthropogenic means?

Possible Answers:

Correct answer:

Explanation:

The only gas in these selections that is made only by man is , which is a CFC or Chlorofluorocarbon. , methane, can be produced by many other organisms; a key example of this are cows. , or water vapor, has many natural origins such as bodies of water, and finally  also has natural sources like volcanoes.

Example Question #4 : Greenhouse Gases

Which of the following accounts for the oscillating levels of  in the atmosphere each year? Choose the MOST correct answer.

Possible Answers:

The revolution of the Earth around the sun

The rotation of the Earth around its axis

The tilt of the earth on its axis

Both the tilt of the Earth on its axis and the Earth's revolution around the sun

Correct answer:

Both the tilt of the Earth on its axis and the Earth's revolution around the sun

Explanation:

The variance of annual  levels can be accounted for by a combination of both the  tilt of the Earth on its axis by as well as the revolution of the Earth around the sun. These two factors in conjunction with one another create the seasons. Since the Northern Hemisphere has vastly more plant coverage compared to the Southern Hemisphere, the Earth can uptake more carbon dioxide during the summer and spring seasons due to high levels of photosynthesis; however, when the Northern Hemisphere is in fall and winter, many of its plants cannot photosynthesize, leading to a spike in atmospheric carbon dioxide.

Example Question #2 : Greenhouse Gases

Each year  levels reach a peak near the same time. In a global context, what happens annually that accounts for such a predictable repeating pattern of these peaks in carbon dioxide?

Possible Answers:

Peak industrial manufacturing occurs

The Northern Hemisphere experiences winter

The Earth is at its closest distance to the sun in its orbit

The transportation industry experiences high volume at that time

Correct answer:

The Northern Hemisphere experiences winter

Explanation:

The Northern hemisphere has a much larger basal area comparatively to that of the Southern hemisphere. When the Northern hemisphere is in winter, many of its plants are not able to photosynthesize, therefore the global  levels rise due to much fewer plants actively uptaking that  for their photosynthetic processes. By the same token, when the Northern hemisphere is experiencing spring and summer, the carbon dioxide levels fall due to higher photosynthetic activity.

Example Question #6 : Greenhouse Gases

Which of the following greenhouse gases is exclusively anthropogenic?

Possible Answers:

Correct answer:

Explanation:

All of these greenhouses gasses, except , occur naturally in the environment.  was produced by humans and was commonly known as Freon-12. It was marketed as a manmade refrigerant and aerosol propellant. 

Example Question #6 : Greenhouse Gases

Which of the following are greenhouse gases?

Possible Answers:

All of these

Carbon dioxide, helium, nitrogen

Carbon dioxide, oxygen, nitrogen

Carbon dioxide, methane, nitrous oxide

Helium, carbon dioxide, water vapor

Correct answer:

Carbon dioxide, methane, nitrous oxide

Explanation:

The greenhouse effect occurs as the temperature within the Earth's atmosphere rises. Greenhouse gases trap the heat within the Earth's atmosphere. As sunlight enters the Earth's atmosphere, it passes through the gaseous layer and the Earth's surface absorbs part of the energy and reflects some energy. These reflected rays of energy get trapped between the Earth's surface and the atmosphere. Some common greenhouse gasses include: carbon dioxide, methane, nitrous oxide, and tropospheric ozone. Helium and nitrogen are two gases in the atmosphere, but they do not contribute to the greenhouse effect.

Example Question #3 : Greenhouse Gases

Methane produced by cattle and other livestock has potential as a renewable, alternative fuel. As commercial farmers worldwide adopt this trend, which of the following would seem a likely effect on global warming? 

Possible Answers:

Burning the methane byproduct for fuel will utilize a potent greenhouse gas, reduce greenhouse gas input into the atmosphere and reduce dependency on energy derived from fossil fuels. 

Burning the methane gas will release carbon dioxide into the atmosphere, contributing further to the greenhouse effect and warming of the planet. 

Since both carbon dioxide and water vapor are emitted when methane is burned, the result will be increased precipitation and increased greenhouse gases in the atmosphere. 

Methane is a potent greenhouse gas and even when it is burned for fuel, the emissions into the atmosphere are equally potent. Whether the methane comes out of the livestock or it is burned, it will contribute equally to global warming. 

When methane is burned, carbon dioxide, which is far more potent a greenhouse gas, is released into the atmosphere. Utilizing methane as fuel will exacerbate the issue of global warming. 

Correct answer:

Burning the methane byproduct for fuel will utilize a potent greenhouse gas, reduce greenhouse gas input into the atmosphere and reduce dependency on energy derived from fossil fuels. 

Explanation:

Methane gas produced by livestock is a very potent greenhouse gas, with molecules that trap far more heat in our atmosphere than carbon dioxide. When methane is burned, carbon dioxide and water vapor are released into the atmosphere, but these vapors have a relatively benign impact on global warming when compared to the release of methane, had it not been used as fuel. Therefore, harvesting methane gas from agricultural waste and livestock prevents potent greenhouse gases from escaping into the atmosphere and also reduces dependence on energy derived from fossil fuels. 

Example Question #4 : Greenhouse Gases

Though their atmospheric levels are much lower than those of , why are chlorofluorocarbons (CFCs) still considered potent greenhouse gases?

Possible Answers:

CFCs are more difficult to remove from chimneys and tailpipes.

CFCs are more efficient at absorbing thermal radiation.

CFCs remain in the atmosphere for only a brief time.

CFCs circulate through the troposphere more quickly than  does.

CFCs do not emit from natural sources.

Correct answer:

CFCs are more efficient at absorbing thermal radiation.

Explanation:

Chlorofluorocarbons, aka CFCs, are nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine. They are used in the production of aerosol sprays, foams and packing materials, as solvents, and as refrigerants. Though mostly inert in the lower atmosphere, that low reactivity affords CFCs a lifespan that can exceed 100 years, giving them time to diffuse into the upper atmosphere and stratosphere. Once in the stratosphere, the sun's ultraviolet (or thermal) radiation is strong enough to cause the cleavage of the  bond, making it an active ozone reducer. Furthermore, CFCs absorb and emit absorb and emit infrared radiation in the wavelength range emitted by Earth, make them potent greenhouse gases.

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