Hydrogen Fuel Cell (College Board AP® Environmental Science): Flashcards
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Define fuel cell.
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Cards in this collection (25)
Define fuel cell.
A fuel cell is a device that converts chemical energy into electrical energy through an electrochemical reaction.
What does a hydrogen-oxygen fuel cell produce?
A hydrogen-oxygen fuel cell produces electricity, water, and heat.
A hydrogen-oxygen fuel cell combines hydrogen, the fuel, with from the air.
A hydrogen-oxygen fuel cell combines hydrogen, the fuel, with oxygen from the air.
True or False?
Like a battery, a fuel cell runs down and needs recharging.
False.
A fuel cell does not run down or need recharging; it generates electricity continuously as long as hydrogen and oxygen are supplied.
Why is the hydrogen-oxygen fuel cell called a clean energy technology?
It is a clean energy technology because it produces no carbon dioxide, particulates, or air pollutants at the point of use.
Which is the most popular type of hydrogen fuel cell?
The proton exchange membrane (PEM) fuel cell is the most popular type of hydrogen fuel cell.
Why are PEM fuel cells well suited to vehicles and portable electronics?
PEM fuel cells work at a low temperature (about 80 °C) and are very powerful, which suits mobile uses.
Phosphoric acid fuel cells are usually used in applications, such as power plants and cogeneration systems.
Phosphoric acid fuel cells are usually used in static applications, such as power plants and cogeneration systems.
True or False?
Phosphoric acid fuel cells have a greater power output than PEM fuel cells.
False.
Phosphoric acid fuel cells have less power output than PEM fuel cells and work at a higher temperature (about 200 °C).
Which type of hydrogen fuel cell works at the highest temperature?
Molten carbonate fuel cells work at the highest temperature, about 650 °C.
What are the main drawbacks of molten carbonate fuel cells?
Molten carbonate fuel cells are very expensive and the most complicated type of hydrogen fuel cell.
Why is hydrogen classed as an energy carrier rather than a primary energy source?
Hydrogen is an energy carrier because it is not available in pure form in nature, so external energy is needed to extract it, for example from water by electrolysis.
True or False?
Producing hydrogen by electrolysis is always carbon-free.
False.
Electrolysis can generate significant carbon emissions if the electricity used comes from fossil fuels.
Define green hydrogen.
Green hydrogen, also called renewable hydrogen, is hydrogen produced using renewable energy sources.
What are the only byproducts of a hydrogen-oxygen fuel cell?
The only byproducts of a hydrogen-oxygen fuel cell are water and heat, so it emits no greenhouse gases.
Why are hydrogen fuel cells highly efficient?
Hydrogen fuel cells convert chemical energy directly into electrical energy, which reduces energy losses.
True or False?
Most hydrogen today is produced from renewable sources.
False.
Most hydrogen is currently produced from fossil fuels, which emits CO₂ in the process.
Hydrogen can be produced from renewable sources such as water, via , or biomass.
Hydrogen can be produced from renewable sources such as water, via electrolysis, or biomass.
Which operating features make fuel cells convenient to use?
Fuel cells operate quietly and have a quick start-up time.
What are some uses of hydrogen fuel cells?
Hydrogen fuel cells can be used in vehicles, backup power systems, and portable electronics.
True or False?
Electrolysis needs only a small energy input to produce hydrogen.
False.
Electrolysis needs large amounts of energy input, which makes hydrogen production challenging.
Why is hydrogen difficult to store and transport?
Hydrogen is difficult to store and transport because it is highly flammable and escapes containment easily.
Fuel cells can over time, especially under high temperatures or varying loads.
Fuel cells can degrade over time, especially under high temperatures or varying loads.
How does the cost of fuel cell systems compare with conventional energy systems?
Fuel cell systems and hydrogen production are expensive compared with conventional energy systems.
Which infrastructure problem limits hydrogen fuel use in transportation?
Hydrogen refueling stations are not widely available, which limits hydrogen fuel use in transportation.
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