electrochemistry

Question 1

explain the function of a salt bridge

Answer 1

a salt bridge connects the two half cells and allows the ions to move across the bridge

it also completes the circuit

Question 2

the aluminium used as the electrode is rubbed with sandpaper to use

suggest the reason why

Answer 2

to remove the oxidised layer on the aluminium

Question 3

explain why electrons flow through the ammeter from the right electrode to the left electrode

Answer 3

the Cu2+ ions are more concentrated at the left hand side so the reaction of Cu2+ with 2e- is more likely to occur

at the right-hand side the reaction: Cu → Cu2+ + 2e- will occur

Question 4

to provide energy for a vehicle, hydrogen can be used either in a fuel cell or in an internal combustion engine

Suggest the main advantage of using hydrogen in a fuel cell rather than an internal combustion engine

Answer 4

in the fuel cell, a greater propotion of energy is available for the kinetic energy of the vehicle

Question 5

Answer 5

H2 + 2OH- → 2H2O + 2e- / H2 → 2H+ + 2e

O2 + 4e- + 2H2O → 4OH-