What will affect the size of the p.d. Produced in a cell?
The type of electrolyte and electrode
The larger the difference in reactivity between the two electrodes the larger the p.d
What is a battery?
Two or more simple cells connected in series
Their voltages are combined to create a larger p.d.
What do electrochemical cells contain?
2 metal electrodes - usually different
An electrolyte
How is a current produced in the cell?
The electrolyte and the 2 electrodes react setting up a potential difference between them, producing a current
What is non-rechargeable battery?
Reaction in a cell is irreversible
This cant be recharged once reactant is used up
What is a rechargeable battery?
The reaction in the cell is reversible
The cell can be recharged by connecting it to an external current, reversing the reaction
What does a fuel cell do?
Uses the electrochemical oxidation of a fuel (such as hydrogen) to produce a p.d
What happens at the anode (-ve) in a hydrogen fuel cell?
The hydrogen is oxidised (loses electrons)
H+ ions move into the electrolyte
What happens at the cathode (+ve) in a hydrogen fuel cell?
Oxygen moves in and is reduced (gains electrons and H+ ions) to form water
Water and heat move out of cell
What is the advantage of a hydrogen fuel cell?
Less pollution over cells lifetime
Don’t need recharging or replacing as often
Cheaper to make
What is the disadvantages of hydrogen fuel cells?
Storage of hydrogen gas takes up space
Hydrogen production can emit greenhouse gases
Hydrogen is explosive - hard to store safely
