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CHEM 113- Unit 5
Question | Answer |
---|---|
ΔG when K is small | positive (non-spontaneous) |
ΔG when K is large | negative (spontaneous) |
redox reactions- acid solutions | balance O with H2O, balance H with H+ |
redox reactions- basic solutions | remove H+ with OH-, reconcile H2O's |
anode | oxidation (metal breaks down, more ions added to solution) |
cathode | reduction (metal builds up, ions removed from solution) |
salt bridge | allow transfer of ions (anions toward anode; cations toward cathode) |
inactive electrodes | electrodes made of something different than the solutions but still transfer electrons |
2 most common inactive electrodes | carbon, poladium, platinum |
voltaic cell notation | inactive electrode|lower ox state|higher ox state||higher ox state|lower ox state|inactive electrode |
Ecell= | cathode-anode |
Voltaic cells are spontaneous when | Ecell>0 |
Reduction potential is based off of | standard hydrogen electrode |
metal activity | higher reduction potential=higher activity |
concentration cell | same metal at the anode and cathode-> differ in concentration (anode is always lower) |
electrolytic cell | external source of power must be greater than Ecell for the forward reaction |
sign of oxidation in an electrolytic cell | + |
sign of reduction in an electrolytic cell | - |
molten salts: what forms at the anode | LESS electronegative non-metal |
molten salts: what forms at the cathode | MORE electronegative metal |