Two types of electrochemical cells 1 Voltaic galvanic spontaneous product favored redox rxn to generate electric current 2 Electrolysis cell uses electric current to cause a nonspontaneous reactant favored rxn to occur Anode oxidation occurs Cathode reduction occurs Reduced Oxidizing Agent Oxidized Reducing Agent Stuff on upper left side of table is stronger oxidizing agent reduced stuff on lower right side is stronger reducing agent oxidized When looking at whether something is being oxidized or reduced look at subscripts not the big numbers Platinum gold and graphite are used as inert electrodes E Cell 0 reactant favored E Cell 0 product favored Farraday s Constant 96 500 C mol e 1 Volt V 1 J C 1 ampere A 1 C s Corrosion oxidation of metals that cause the metal to deteriorate Fe2O3 H2O The water is a solution of ionic compounds NaCl Think of this as a voltaic cell Water is the anode and iron is the cathode The solution serves as a salt bridge and the iron itself acts as a conductor Zinc and Iron Write what happens Corrosion control 1 cover the surface 2 sacrificial metal Sacrificial metal galvanized steel surface covered with Zn s Al2O3 sticks to the Al surface it prevents additional oxygen from getting to Al surface you don t get further erosion already a thin layer of corrosion on the surface Oscillating rxn multiple step rxn orange dark blue clear this cycle continues to occur with stir bar
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