Hydrogen Fuel Cell - AP Environmental Science

What is the advantage of hydrogen fuel cells in terms of noise pollution?

They operate quietly. No moving parts or combustion makes fuel cells nearly silent.
What is a challenge of storing hydrogen for fuel cells?

Hydrogen has low energy density per volume. Gaseous hydrogen requires high-pressure tanks or cryogenic storage.
Identify an alternative to platinum as a catalyst in fuel cells.

Nickel or cobalt can be alternatives. Lower-cost metals being developed to replace expensive platinum.
Which gas is released as a waste product in traditional combustion engines?

Carbon dioxide (CO $_2$ ) is released. Burning fossil fuels produces CO $_2$ as a major greenhouse gas emission.
Identify the environmental benefit of using hydrogen fuel cells.

They reduce greenhouse gas emissions. Water vapor emission instead of CO $_2$ helps combat climate change.
Identify a disadvantage of using platinum in fuel cells.

Platinum is expensive and scarce. High cost and limited supply make platinum catalysts expensive.
What is the anode reaction in a hydrogen fuel cell?

$2H_2 \rightarrow 4H^+ + 4e^-$ . Hydrogen molecules lose electrons at the anode, becoming protons.
State the main advantage of hydrogen fuel cells over fossil fuels.

They produce no harmful emissions. Only water vapor is emitted, unlike fossil fuels that release greenhouse gases.
What is the role of the catalyst in a hydrogen fuel cell?

It speeds up the chemical reaction. Lowers activation energy needed for hydrogen oxidation and oxygen reduction.
What is the energy source for electrolysis of water?

Electricity is the energy source. Electric current provides energy to break water's molecular bonds.
What kind of energy transformation occurs in a hydrogen fuel cell?

Chemical energy to electrical energy. Direct conversion without thermal combustion intermediates.
What is the byproduct of a hydrogen fuel cell?

Water is the byproduct. The only emission from the electrochemical reaction between hydrogen and oxygen.
What is the role of the electrolyte in a hydrogen fuel cell?

It conducts protons from anode to cathode. Facilitates proton transport while maintaining electrical separation.
What type of fuel cell is most common in vehicles?

Proton exchange membrane fuel cell (PEMFC). Low operating temperature and compact design suit automotive applications.
Which component of the fuel cell lets protons pass but not electrons?

The proton exchange membrane (PEM). Selective permeability allows ionic conduction while blocking electrons.
In a hydrogen fuel cell, what carries electrons from anode to cathode?

An external circuit carries the electrons. Electrons flow through the external circuit to complete the electrical loop.
Describe the efficiency of hydrogen fuel cells compared to combustion engines.

Fuel cells are generally more efficient. Fuel cells convert energy directly without combustion losses.
What is the role of the bipolar plates in a fuel cell?

They conduct electrons and distribute gases. Manage electrical current flow and distribute reactant gases evenly.
Identify the main component used as a fuel in hydrogen fuel cells.

Hydrogen gas is the main fuel component. Hydrogen gas provides the protons and electrons needed for the reaction.
Identify one application of hydrogen fuel cells.

They are used in transportation, such as fuel cell vehicles. Cars, buses, and trucks can run on hydrogen fuel cells for zero emissions.
Name the catalyst often used in hydrogen fuel cells.

Platinum is often used as a catalyst. Platinum's properties make it highly effective for fuel cell reactions.
What is the typical operating temperature for PEM fuel cells?

Around 80°C (176°F). Optimal temperature for efficient proton conduction in the membrane.
Which pollutant is not produced by hydrogen fuel cells?

Nitrogen oxides (NO $_x$ ) are not produced. Clean electrochemical process avoids high-temperature combustion pollutants.
What is the efficiency range of hydrogen fuel cells?

Typically 40% to 60% efficient. Higher than internal combustion engines due to direct energy conversion.
What is the energy density of hydrogen compared to gasoline?

Hydrogen has a higher energy density by weight. Hydrogen contains more energy per kilogram than gasoline.
What is the primary purpose of a hydrogen fuel cell?

To convert chemical energy into electrical energy. Converts hydrogen's chemical bonds into usable electricity through electrochemical reactions.
Identify a key limitation of hydrogen production via electrolysis.

It is energy-intensive and costly. Requires significant electrical input, making it expensive to operate.
Which sector benefits from using hydrogen fuel cells for cleaner energy?

The transportation sector benefits. Vehicles can achieve zero local emissions using hydrogen power.
What is the main environmental advantage of hydrogen fuel cells?

Reduction in air pollution. Zero harmful emissions improve urban air quality significantly.
What is the chemical reaction formula in a hydrogen fuel cell?

$2H_2 + O_2 \rightarrow 2H_2O + \text{electricity}$ . Shows hydrogen and oxygen combining to produce water and electrical energy.
What is a common method of producing hydrogen for fuel cells?

Electrolysis of water is common. Electric current splits water molecules into hydrogen and oxygen gases.
What is the cathode reaction in a hydrogen fuel cell?

$O_2 + 4H^+ + 4e^- \rightarrow 2H_2O$ . Oxygen gains electrons and protons at the cathode to form water.
What is a benefit of hydrogen fuel cells in space applications?

They provide water as a byproduct. Astronauts can drink the water produced as a valuable resource.
Which part of the hydrogen fuel cell separates hydrogen and oxygen?

The proton exchange membrane (PEM). Selectively allows protons to pass while blocking electrons and gases.
How are hydrogen fuel cells different from batteries?

Fuel cells require a continuous supply of fuel. Batteries store energy internally; fuel cells need external fuel input.
What is the typical voltage output of a single hydrogen fuel cell?

Approximately 0.7 volts per cell. Standard output for proton exchange membrane fuel cells under normal conditions.
What is the main challenge in using hydrogen fuel cells?

The storage and transportation of hydrogen. Hydrogen is highly flammable and requires specialized containment systems.
Which two elements are essential in a hydrogen fuel cell?

Hydrogen and oxygen are essential. Hydrogen provides protons and electrons, oxygen accepts them to form water.
What is the main component of the exhaust from a hydrogen fuel cell?

Water vapor is the main component. Clean water vapor is the only emission from hydrogen fuel cells.

Study these flashcards