Hydrogen fuel cells Cambridge IGCSE Co-ordinated Sciences (Double Award) revision
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In plain words
A fuel cell is like a battery that never runs flat as long as you keep feeding it fuel. A hydrogen–oxygen fuel cell takes in hydrogen and oxygen, makes electricity, and gives out only water.
Three things to know
- In a hydrogen–oxygen fuel cell, hydrogen and oxygen react to produce electricity. Water is the only chemical product: 2H₂ + O₂ → 2H₂O.
- Advantages over a petrol engine: no carbon dioxide or other pollutants where it is used, and more of the energy ends up doing something useful.
- Disadvantages: hydrogen is a flammable gas that is hard to store and transport, there are few places to refuel, and most hydrogen is still made from fossil fuels.
Tips and tricks
- "The only product is water" is the key fact. Write it whenever fuel cells come up.
- Be fair in comparisons: a fuel cell car gives out no carbon dioxide itself, but making the hydrogen may have done.
It lands in your notebook with its questions as flashcards.
Hydrogen fuel cells: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
What is the only chemical product of a hydrogen–oxygen fuel cell?
Hydrogen and oxygen combine: 2H₂ + O₂ → 2H₂O.
Which two substances are fed into a hydrogen–oxygen fuel cell?
They react to release energy as electricity.
What is an advantage of a fuel cell over a petrol engine?
Its only product is water.
What is a disadvantage of hydrogen as a fuel for cars?
It is a gas, so it needs strong, high-pressure tanks.
A fuel cell changes chemical energy directly into what?
That electricity can drive a motor.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 5 marks. Write your answers on paper, then check them.
Hydrogen fuel cells
Cambridge IGCSE Co-ordinated Sciences (Double Award) 0654 · 5 marks · papermunch.org
Name ______________________________ Date ______________
Name the only chemical product of a hydrogen–oxygen fuel cell.[1]
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Water.
Give two advantages of a hydrogen fuel cell over a petrol engine in a car.[2]
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Any two: it produces only water (no carbon dioxide or other pollutants); it is more efficient; it is quieter.
Give two disadvantages of using hydrogen fuel cells in cars.[2]
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Any two: hydrogen is difficult and bulky to store; it is flammable; there are few filling stations; hydrogen is usually made from fossil fuels; fuel cells are expensive.
Answers: Hydrogen fuel cells
- 1. Water.
- 2. Any two: it produces only water (no carbon dioxide or other pollutants); it is more efficient; it is quieter.
- 3. Any two: hydrogen is difficult and bulky to store; it is flammable; there are few filling stations; hydrogen is usually made from fossil fuels; fuel cells are expensive.