Download presentation
Presentation is loading. Please wait.
Published byScot Martin Modified over 8 years ago
1
D.C. SOURCE (BATTERY) + + + Au 3+ 2e- ELECTROLYSIS OF A SALT SLIDE ONE OVERVIEW ANIMATION 2e- Au 3+ 3e- - - - - - Au 0 THE ELECTROLYTE SOLUTION, USUALLY H 2 SO 4 THE ANODE IS SOLID Pt or GRAPHITE,AND DOES NOT REACT IN REDOX (INERT) THE CATHODE IS A CHEAP PIECE OF CONDUCTIVE MATERIAL. THIS COULD BE ANY CONDUCTIVE (METAL) IN JEWELRY TO BE GOLD PLATED. THIS COULD BE A HEART CHARM BRACELET PIECE TO BE GOLD PLATED THE SOURCE OF GOLD IS AuCl 3 ( THE THREE CHLORIDES ARE -1 EACH SO THE Au MUST BE 3+. Cl - Cl 2
2
D.C. SOURCE (BATTERY) + + + Au 3+ 2e- ELECTROLYSIS, SALT SLIDE TWO NON SPONTANEOUS OXIDATION AT ANODE The anode (PLATINUM) IS ELECTRON POOR DUE THE DC SOURCE “PUMPING” OUT ELECTRONS. THE CHLORIDE IONS ARE ATTRACTED TO THE + CHARGE OF THE ANODE.REMEMBER HALOGENS REACT IN PAIRS! An important characteristic of the electrolytic cell is that the oxidation of a LESS active non-metal (bottom position on table J). - - - - 2Cl - (aq) + Cl 2 0 (g) 2e- OXIDATION AT ANODE Cl - Cl 2 (DEADLY Cl 2 GAS BUBBLES OUT AT ANODE.)
3
D.C. SOURCE (BATTERY) + + + - - Au 3+ 2e- 2 e - ELECTROLYSIS, OF A SALT SLIDE THREE ELECTRON FLOW 2e- THE D.C. SOURCE ACTIVLEY “PUMPS” ELECTRONS OUT OF THE ANODE CAUSING IT TO BE RELATIVLEY POSITIVE COMPARED TO THE CATHODE. THE D.C. SOURCE ACTIVLEY “PUMPS” ELECTRONS ITO THE CATHODE, CAUSING IT TO BE NEGATIVE RELATIVE TO THE ANODE. THIS HIGH DENSITY OF ELECTRONS AT THE CATHODE WILL “FORCE” A REDUCTION TO OCCUR. - - - Cl - Cl 2
4
D.C. SOURCE (BATTERY) Au + + + Au 3+ 2e- Au 3+ 3e- ELECTROLYSIS SALT SLIDE FOUR NON SPONTANEOUS REDUCTION AT CATHODE 2e- THE CHLORIDE IONS CONTINUE TO MIGRATE TO THE ANODE AS THE GOLD MIGRATES TO THE ANODE. THE GOLD(III) CATIONS MIGRATE TO THE ELECTRON RICH, NEGATIVELY CHARGED CATHODE WHERE THEY WILL BE FORCED TO BE REDUCED TO Au 0 SOLID. THE SOLID GOLD THAT WAS PRODUCED DURING REDUCTION ELECTROPLATE S THE CATHODE AS SOLID GOLD Au 0 - - - + Au 3+ 3e- REDUCTION AT CATHODE Cl - Cl 2 Cl -
5
2Cl - (aq) + Cl 2 0 (g) 2e-Au 0 + Au 3+ 3e- BALANCING THE HALF REACTIONS 3( 2Cl - (aq) + Cl 2 0 (g) 2e - )Au 0 ) + 2(Au 3+ 3e- THE ELECTRONS MUST CANCEL, THE LCD IS 6, FACTORS ARE 3 AND 2. 6Cl - (aq) + 3Cl 2 0 (g) 6e-2Au 0 + 2Au 3+ 6e- 2Au 3+ (aq) + 6Cl - (aq) + 3Cl 2 0 (g) 2Au 3+ (aq)
6
REVIEW OF ELECTROCHEMICAL CELL TYPES VOLTAIC CELLELECTROLYTIC CELL SPONTANEITYSPONTANEOUSNOT SPONTANEOUS METAL OXIDIZEDTOP OF TABLE “J”BOTTOM OF “J” CATHODE REDUCTION IN BOTH CELLS POSITIVE:SPONTANEOUS REDUCTION CONSUMES ELECTRONS. NEGATIVE: DC SOURCE (BATTERY) FORCES ELECTRONS HERE. ANODE OXIDATION IN BOTH CELLS NEGATIVE: SPONTANEOUS OXIDATION SUPPLIES ELECTRONS HERE. POSITIVE: D.C. SOURCE PULLS ELECTRONS OUT. ENERGYEXOTHERMICENDOTHERMIC ELECTRON FLOW FROM ANODE TO CATHODE ELECTRON GRADIENT HIGH TO LOW ENERGY LOW TO HIGH ENERGY
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.