Question 1: Define a hydrogen fuel cell and briefly describe how it generates electricity.

Answer: A hydrogen fuel cell is a device that converts chemical energy from hydrogen and oxygen into electrical energy through electrochemical reactions, producing water as the only waste product.

Question 2: Explain the role of the electrolyte in a hydrogen fuel cell.

Answer: The electrolyte conducts ions between the anode and cathode, allowing the electrochemical reactions to occur while preventing the direct mixing of hydrogen and oxygen gases.

Question 3: What are the main advantages of using hydrogen fuel cells over traditional combustion engines?

Answer: Hydrogen fuel cells produce only water as waste, have higher efficiency, emit no pollutants during operation, and can be refuelled quickly compared to batteries.

Question 4: Calculate the voltage produced by a hydrogen fuel cell that operates with a standard potential of 1.23 V under ideal conditions.

Answer: 1.23 V

Question 5: Identify two safety precautions that should be observed when handling hydrogen gas in a fuel cell experiment.

Answer: Ensure proper ventilation to prevent accumulation of hydrogen, and avoid sources of sparks or flames due to hydrogen's flammability.

Question 1: Design a simple theoretical experiment to test the electrical output of a hydrogen fuel cell. Describe the variables involved and the safety precautions necessary.

Answer: The experiment involves connecting the hydrogen fuel cell to a voltmeter to measure voltage output. Variables include hydrogen supply pressure, temperature, and electrode materials. Safety precautions include working in a well-ventilated area, wearing protective equipment, and ensuring no ignition sources are nearby due to hydrogen's flammability.

Question 2: Describe how hydrogen fuel cells could be used to power vehicles and discuss one potential challenge of this application.

Answer: Hydrogen fuel cells can be installed in vehicles to generate electricity that powers electric motors, offering zero emissions. A challenge is the lack of widespread hydrogen refuelling infrastructure and the high costs of fuel cell technology.

Question 3: In a scenario where 2 mol of hydrogen reacts in a fuel cell, how many moles of water are produced? (Reaction: 2H₂ + O₂ → 2H₂O)

Answer: 2 mol of water

Question 4: Explain why hydrogen fuel cells are considered more environmentally friendly than fossil fuel combustion engines.

Answer: Hydrogen fuel cells produce only water as a waste product, emit no greenhouse gases during operation, and do not release pollutants like nitrogen oxides or sulphur dioxide, making them cleaner for the environment.