Electro-chemistry: Batteries and plating Electrochemistry: The study of the interchange of chemical and electrical energy Oxidation is the loss of electrons (Increase in charge). OIL Reduction is the gain of electrons (Decrease in charge) RIG

2 metals and 2 solutions of the same metal (ions) The more active metal will LOSE electrons to the less active metal (it’s ions) which will GAIN Electrons You need:

Electrochemical Cells: 1.Voltaic Cells: Produces electrical current spontaneous chemical reactions  ex. Battery 2. Electrolytic Cells Consumes electrical current non-spontaneous and require electricity or battery  ex. Electrolysis, electroplating Device capable of either generating electrical energy from chemical reactions or facilitating chemical reactions through the introduction of electrical energy

Parts of the voltaic cell… Anode  the electrode where oxidation occurs After a period of time, the anode may appear to become smaller as it falls into solution. Cathode  the electrode where reduction occurs After a period of time it may appear larger, due to ions from solution plating onto it. Salt Bridge  a device used to maintain electrical neutrality in a voltaic cell. This may be filled with a salt solution. Electron Flow  always from anode to cathode (through the wire) Ion Flow  always through the salt bridge

Anode Cathode

Electricity can be made from a spontaneous redox reaction, instead of heat, light... 2 half cells 1 side loses electrons to the other side that gains Zinc metal Zn solution like ZnSO 4 (aq) The more active metal looses, higher on Chart J Copper metal Cu solution like CuSO 4 (aq) “ Dead” battery has reached equilibrium, volts = 0 e - ’s flows on wire Zn 0  Zn e - Cu e -  Cu 0 LEO anode GER cathode (also called electrochemical cells) measured in volts - ions flow in salt bridge 2 or more cells = a battery

Redox reactions that are not spontaneous and require electricity Electrolysis : splitting a chemical apart into its elements using electricity battery H2OH2O H 2 O  H 2 (g) + O 2 (g) + + H e -  H 0 GER (cathode) O -2  O 0 + 2e - LEO (anode)

Electroplating : adding a layer of a metal onto another metal metal for plating fork to be plated solution with metal ions (usually expensive metals onto cheaper metal) Ag Ag + Ag + + 1e -  Ag 0 reduction cathode Ag 0  Ag e - oxidation anode - + battery (Requires electricity or a battery)