Topic 19.1: Electrochemical cells Flashcards
Cell potential definition
Potential difference between two electrodes in a voltaic cell
What does a voltaic cell generate?
Electromotive force
Standard conditions for cell potential
a) 298 K
b) 100 kPa
c) 1 M
Standard cell potential (Formula)
a) E(Cathode) - E (anode)
Standard hydrogen electrode
Half-cell
a) 1 M H+
b) 298 K
c) H2(g) at 100 kPa
d) Pt electrode
Gibbs free energy from cell potential (Formula)
∆G = -nFE
Factors affecting the amount of product in electrolysis
a) Time
b) Current
c) Charge
Reduction of water (Cathode)
2H2O + 2e- => H2 + 2OH-
Oxidation of water (Anode)
2H2O => 4H+ + O2 + 4e-
Possible products of hydrolysis in aqueous solutions in cathode
a) Very reactive metals – H2 (g)
b) Unreactive metals – Production of metals
Possible products of hydrolysis in aqueous solutions in anode
a) Br2 / I2 oxidized rather than H2O
b) SO4 2- / NO3- produce O2(g)
What is produced in the anode at high concentrations of NaCl?
Cl2(g)
What is produced by the electrolysis of CuSO4 using inert electrodes in:
a) Anode
b) Cathode
a) O2
b) Cu
What is produced by the electrolysis of CuSO4 using copper electrodes in:
a) Anode
b) Cathode
a) Copper ions pass into solution
b) Production of copper at the cathode
Definition of electroplating
Process of using electrolysis to deposit a layer of a metal on top of another object
Components of an electrolytic cell for electroplating:
a) Electrolyte
b) Cathode
c) Anode
a) Ions which are to be deposited
b) Object to be plated
c) Metal which is coated
Purpose of electroplating
a) Decorative purposes
b) Corrosion control
c) Improvement of function
