Hydrogen Fuel Cell
A fuel cell is something that can convert chemical energy into electrical energy. A fuel cell is a lot like a battery. It has two poles where the reactions take place and an electrolyte which carries the charged particles from one pole to the other. In order for a fuel cell to work, it needs hydrogen (H2) and oxygen (O2). The hydrogen enters the fuel cell at the negative pole. A chemical reaction strips the hydrogen molecules of their electrons and the atoms become ionized to form H+. The electrons travel through wires to provide a current to do work. The oxygen enters at the positive pole, usually from the air. The oxygen picks up the electrons that have completed their circuit. The oxygen then combines with the ionized hydrogen atoms (H+), and water (H2O) is formed as the waste product which exits the fuel cell. The electrolyte plays an essential role as well. It only allows the appropriate ions to pass between the poles. If other ions were allowed to flow between the anode and cathode, the chemical reactions within the cell would be disrupted.
The reaction in a single fuel cell typically produces only about 0.7 volts. Therefore, fuel cells are usually stacked or connected in some way to form a fuel cell system that can be used in cars, generators, or other products that require power. Let's have a look at what a Hydrogen Fuel Cell looks like:
Watch the video below and answer the questions in your book:
Important!!! This is confusing! Remember fuel cells are the opposite of electrolysis.
The 'anode' is the NEGATIVE POLE as this is where the electrons are produced.
The 'cathode' is the POSITIVE POLE.
1. What can fuel cells be used for?
2. How efficient is a car engine? How does this compare to a fuel cell?
3. What is the overall equation for a hydrogen fuel cell?
4. Describe what occurs at the negative pole. Use an equation in your answer.
5. Describe what occurs at the positive pole. Use an equation in your answer.
6. In which direction do the electrons flow?
Advantages and Disadvantages
In your book, create a table to show the advantages and disadvantages of using hydrogen as a fuel. Hint: Think about pollution and safety!