Electrochemical cells

Question 1

Salt Bridge

Answer 1

• used to connect up the circuit

- the free moving ions conduct the charge

Question 2

Advantages of Fuel cells

Answer 2

(i) less pollution and less CO2. (Pure hydrogen emits only water whilst hydrogen-rich fuels produce only small amounts of air pollutants and CO2).
(ii) greater efficiency

Question 3

Limitations of hydrogen fuel cells

Answer 3

(i) expensive
(ii) storing and transporting hydrogen, in terms of safety, feasibility of a pressurised liquid and a limited life cycle of a solid ‘adsorber’ or ‘absorber’
(iii) limited lifetime (requiring regular replacement and disposal) and high production costs,
(iv) use of toxic chemicals in their production

Question 4

Fuel cell

Answer 4

a fuel cell uses the energy from the reaction of a fuel with oxygen to create a voltage