Fossil Fuels (College Board AP® Environmental Science): Flashcards
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Define combustion.
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Cards in this collection (43)
Define combustion.
Combustion is a quick thermochemical reaction that requires a fuel, oxygen, and an ignition or trigger.
Why is combustion described as an exothermic reaction?
Combustion is exothermic because it releases heat, along with light in the form of a flame.
Complete combustion of a hydrocarbon occurs when there is oxygen.
Complete combustion of a hydrocarbon occurs when there is excess oxygen.
What are the products of incomplete combustion of a hydrocarbon?
Incomplete combustion, caused by insufficient oxygen, produces unburned fuel (soot), carbon monoxide, and water.
True or False?
Natural gas produces more CO₂ than coal when burned to generate electricity.
False.
Coal produces more CO₂ than any other fossil fuel when burned to generate electricity.
Which toxic elements are found in the ash from burning coal?
Coal ash is toxic because it contains lead, mercury, and arsenic, which can leak from ash ponds into the ground, surface water, or soil.
Which pollutants released by burning coal contribute to smog and acid rain?
Burning coal releases sulfur oxides and nitrogen oxides, which are irritants that contribute to smog and acid rain.
What is the main contributor to rising carbon dioxide levels in the atmosphere?
The continued burning of fossil fuels is the main contributor to rising atmospheric carbon dioxide levels.
In a fossil fuel power station, steam turns a turbine, which turns a to produce electricity.
In a fossil fuel power station, steam turns a turbine, which turns a generator to produce electricity.
What sequence of energy changes takes place in a steam-turbine power station?
Chemical energy in the fuel becomes thermal energy in the steam, then mechanical energy in the turbine, and finally electrical energy from the generator.
True or False?
Coal is a more efficient fuel than natural gas for generating electricity.
False.
Coal is approximately 30% efficient, whereas natural gas is roughly 60% efficient at generating electricity.
What happens to the steam after it has turned the turbine?
The steam is condensed back into water so it can be used again.
True or False?
Drilling is used to extract solid fuels such as coal.
False.
Mining extracts solid fuels such as coal and uranium, while drilling extracts gaseous or liquid fuels such as natural gas and crude oil.
What is the advantage of horizontal drilling?
Horizontal drilling uses a steerable drill bit and reduces the number of wells needed.
Define acidizing.
Acidizing is a technique that dissolves rocks blocking the path of the fuel.
Roughly how much of a reservoir's oil is extracted in stage one of oil extraction?
Roughly 15% of a reservoir's oil is extracted in stage one, by drilling and pumping at normal pressure.
What happens in stage three of oil extraction?
In stage three, steam, carbon dioxide, or nitrogen gas is pumped into the reservoir to drive leftover oil toward the wellhead. This stage is very expensive.
Strip-mining causes considerable environmental damage through and habitat destruction.
Strip-mining causes considerable environmental damage through erosion and habitat destruction.
Why is sub-surface coal mining more hazardous for miners than strip mining?
Sub-surface mining is more hazardous for miners because of tunnel collapses and gas explosions, although it is less damaging to the surface environment.
Define mountaintop mining.
Mountaintop mining is a surface mining practice that removes mountaintops to expose coal seams and dumps the mining waste in adjacent valleys, known as valley fills.
Define conventional natural gas.
Conventional natural gas is gas trapped under a layer of rock that can be drilled into, usually found together with oil deposits.
Define tight gas.
Tight gas is natural gas trapped in an impermeable rock formation, so it can only be extracted by fracking and acidizing.
Why is extracting natural gas from shale costly?
Shale is a fine-grained, layered sedimentary rock that is hard to drill into, making extraction costly.
Which fossil fuel is most commonly used to generate electricity in the U.S.?
Natural gas is the fossil fuel most commonly used to generate electricity in the U.S.
True or False?
Natural gas is the most polluting of the fossil fuels.
False.
Natural gas is the least polluting of the fossil fuels, although it still releases CO₂ and causes air pollution.
What is a major environmental risk of using oil, as shown by the Exxon Valdez?
A major environmental risk of using oil is oil spills, such as the Exxon Valdez spill.
Burning coal releases SO₂, which leads to .
Burning coal releases SO₂, which leads to acid rain.
What are the main advantages of coal as an energy source?
Coal has large world reserves, is cheap, reliable, and easy to produce energy from.
Define tar sands.
Tar sands are reservoirs of bitumen, which is a heavy crude oil.
True or False?
Nuclear power stations release large amounts of greenhouse gases.
False.
Nuclear power produces no greenhouse gas emissions; its other advantages include high efficiency and needing only small amounts of uranium.
Why is nuclear waste a disadvantage of nuclear power?
Nuclear waste is radioactive and expensive to dispose of.
Which two nuclear accidents illustrate the risks of nuclear power?
The Chernobyl and Fukushima accidents illustrate the risks of nuclear power.
How can tar sand extraction affect human health?
Tar sand extraction causes higher rates of air pollution, with possible links to higher cancer rates.
True or False?
Extracting oil from tar sands uses very little water.
False.
Tar sand extraction is very water-intensive, and the contaminated water is stored in ponds, from which wastewater can leak into water sources.
When is extracting oil from tar sands cost-effective?
Tar sand extraction is expensive, so it is only cost-effective when oil prices are high.
Greenhouse gas emissions from bitumen are than from conventional oil.
Greenhouse gas emissions from bitumen are higher than from conventional oil.
How does tar sand mining affect wildlife?
Tar sand mining destroys natural habitats through open-pit mines and deforestation, causing declines in caribou, lynx, and wolverine populations.
Define fracking.
Fracking is the extraction of shale gas by pumping a mixture of sand, chemicals, and water into shale rock at high pressure, shattering the rock to release the gas.
How does fracking increase a country's energy security?
Fracking reduces reliance on gas imports, which increases energy security.
True or False?
Fracking has no link to seismic activity.
False.
Fracking has been linked to an increase in earthquakes.
How can fracking affect water supplies?
The fluid used in fracking may contaminate water supplies, and the process uses large quantities of water.
Which greenhouse gas can be emitted during fracking?
Fracking can emit methane.
What are the economic advantages of fracking for local people?
Fracking increases employment and reduces people's energy bills.
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