click below
click below
Normal Size Small Size show me how
chem lecture ch19
Question | Answer |
---|---|
Galvanic cells | they use redox reactions to generate electricity. The energy comes from a spontaneous redox reaction, and the electron transfer is forced to take place through a wire. |
cathode | is the electrode at which reduction takes place |
anode | is the electrode at which oxidation takes place |
Cations move towards the _____? | cathode |
Anions move towards the _____? | anode |
salt bridge | a tube filled with a solution containing ions not involved in the cell reaction. |
potential | magnitude of this ability is called the potential in ( V ). The volt is the amount of energy in joules, that can be delivered per coulomb ( C ). So, a charge flowing under a potential of one volt can deliver one joule of energy per coulomb. 1 V = 1 J / C |
cell potential ( Ecell ) | The maximum potential a galvanic cell can generate. It depends on the composition of the electrodes, the concentrations of the ions in the half-cells and the temperature. |
Reduction potential | measure of the tendency of reduction half-reactions to occur. The magnitude of this tendency is expressed by the half-reaction’s reduction potential. |
E°cell formula | E°cell = E°Ag+ - E°Cu2+ |
the calculated standard cell potential for the spontaneous reaction is always ________? | posotive |
cell potential formula | G = maximum work = n F Ecell n=number of moles of electrons transferred, F=Faraday constant The Faraday constant F is equal to the coulombs of charge equivalent to one mole of electrons (9.65 104 Coulombs per mole of electrons). |
If G is negative, which corresponds to a positive value of Ecell, the reaction will occur ____________? | spontaneously |
pH-electrode | a galvanic cell with a potential, that is proportional to the proton concentration in the solutions into which it is immersed. |
In an electrolytic cell: Cathode is _______? Anode is ________? | cathode is negative anode is positive |