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Chemistry

GCSE · AQA

QuestionsFlashcards

Simple Model of the Atom
The Periodic Table
Properties of Transition Metals
- Typical Properties of Transition Metals
  7
- Transition Metals vs. Alkali Metals
  6

Ionic, Covalent & Metallic Bond
Bonding & Substance Properties
Structure & Bonding of Carbon
Bulk & Surface Properties
- Sizes of Particles & their Properties
  6
- Nanoparticles
  6

Formation of Earth's Atmosphere
CO2 & CH4 as Greenhouse Gases
Causes of Atmospheric Pollution
- Atmospheric Pollutants from Fuels
  6
- Properties & Effects of Atmospheric Pollutants
  6

Global Reserves & Potable Water
Life Cycle Analysis & Recycling
- Life Cycle Assessment
  7
- Reducing Use of Resources
  5
Using Materials
Haber Process & NPK Fertilisers

Fuel Cells Flashcards

All 6 cards in this deck

What is a fuel cell?: A cell supplied by an external source of fuel (e.g. hydrogen) and oxygen or air, in which the fuel is oxidised electrochemically to produce a potential difference.
What is the overall equation for the reaction in a hydrogen fuel cell?: $2\mathrm{H_2} + \mathrm{O_2} \rightarrow 2\mathrm{H_2O}$
How does a hydrogen fuel cell produce a potential difference?: Hydrogen is oxidised electrochemically (it loses electrons) to produce water.
Give two advantages of hydrogen fuel cells compared with rechargeable cells and batteries.: No toxic chemicals to dispose of at the end of the cell's life; they take less time to refuel and travel further before refuelling; no loss of efficiency over time.
Give two disadvantages of hydrogen fuel cells compared with rechargeable cells and batteries.: Hydrogen is a highly flammable gas that is difficult to store and there are few refuelling stations; energy is needed to produce the hydrogen fuel.
True or false? A hydrogen fuel cell must be recharged from an external electrical supply once its reactants run out.: False. It keeps producing a potential difference as long as hydrogen and oxygen are supplied from outside the cell.