Types of cells. Source or use of electricity. Electrode. Cell. –. Molten or aqueous chemicals. +. –. +. –. +. Overview. “Cells” are containers of liquid with electrodes:. In “electrolytic cells”, electricity is used to force chemicals to undergo a redox reaction
Molten or aqueous chemicals
1) What in this room is a product of electrolysis?
2) Are ions at the anode gaining or losing electrons? What about at the cathode?
3) How is the conduction of electricity in a wire different from in an electrolytic cell.
4) Will electricity be conducted indefinitely through an electrolytic cell? Explain.
5) 697 gives the cell reaction for the electrolysis of NaCl. Write half reactions and the cell reaction for the electrolysis of HF(aq)
1) Aluminum cans, copper wires
2) Anode = oxidation = loss of electrons (LEO)
Cathode= reduction= gain of electrons (GER)
3) In wire, electricity means flow of electrons past metal atoms. In electrolysis, electricity means the movement of ions.
4) No. Only until all of the ions are used up.
5) 2H+(aq) + 2e– H2 (cathode / reduction)
2F–(aq) F2 + 2e– (anode / oxidation)
2H+(aq) + 2F–(aq) H2(g) + F2(g)
Read over study note
___ + _e– ___ ___ ___ + _e–
1) Where in the room is there a galvanic cell?
2) In fig.17.12, is a solution with Cu2+ needed for the Cu half-cell to conduct? Is a solution containing Ag+ needed for the Ag half-cell?
3) Looking at 17.12, which electrode is losing electrons, which is gaining electrons, which is reduction, which is oxidation?
4) How do anodes and cathodes differ between electrolytic and galvanic cells?
1) Batteries (computer, walkman) are galvanic
2) Cu2+ in unnecessary since it comes off of the Cu electrode, Ag+ is needed because this is deposited onto the Ag electrode
3) Cu is losing electrons to become Cu2+(oxidation), Ag+ is gaining electrons to become Ag (reduction).
4) In both, oxidation occurs at the anode and reduction at the cathode.
Electrolytic: anode = + ve, cathode = – ve.
Galvanic: anode = – ve, cathode = + ve