Chemical and fuel cells Flashcards
Chemical cells definition
converts chemical energy into electrical energy through a redox reaction, the more reactive metals loses its electrons (oxidation), when 2 different metal electrodes re placed into a electrolyte
Chemical cells - when is a larger voltage produced
the larger the difference between metals in the electrochemical series the larger the potential difference produced
Factors that affect voltage of a cell
type of metal electrodes, type of electrolyte, concentration of the electrolyte
Chemical cell types
non-rechargeable (alkaline), rechargeable (lithium ion batteries)
Non-rechargeable (alkaline) battery definition
chemical reaction stops when reactants are used up (discharged)
Rechargeable (lithium ion) batteries definition
can be discharged and charged many times but not forever
Hydrogen fuel cells definition
hydrogen is oxidised producing water and potential difference, it travels through the electrolyte membrane to the negative electrode
Advantages of hydrogen fuel cells
converts chemical energy directly into electrical energy, waste gas is water which is not polluting, lightweight and small, no moving parts so unlikely to break down, can be used continuously - do not need to be recharged
Disadvantages of hydrogen fuel cells
fuel cells are expensive to manufacture, hydrogen us expensive to produce, it takes up a lot of space in a tank, it is an explosive gas, few hydrogen fuel filling stations
Hydrogen fuel cells half equation at positive electrode
2H2 – 4e-→ 4H+
Hydrogen fuel cells half equation at positive electrode
O2 + 4H+ + 4e-→ 2H2O
How to chemical cells work
2 metals are placed in an electrolyte and the electrons flow from the most reactive metal to the less reactive metal, the most reactive metal lose electrons and the least reactive metal gains electrons
Battery consists of
2 more more cells connected together in series which provides a greater potential difference
