Redox/Galvanic/Fuel Cells Flashcards
Oxidation number laws
C = +4
O = -2
H = +1
Electrochemical series
- ↑ going up on the left side (Strongest oxidant)
- going down on the right side (Strongest reductant) ↓
Limitations:
1. Results of series are 1M concentrations and are measured at 25 degrees
2. Gases are at SLC
3. When the conditions change it may alter the order of the series
Writing half equations
- KOHES
- KOHES456
- CHOOE
- CHOxE
KOHES
K- Key element
O- Oxygen with H2O
H- Hydrogen with H+
E- Electrons
S- States
KOHES456
K- Key element
O- Oxygen with H2O
H- Hydrogen with H+
4- add OH- to both sides of equations to balance H+
5- combine OH- with H+ to form water
6- cancel waters
E- Electrons
S- States
Define galvanic cell
- spontaneous reaction where chemical energy is converted into electrical
- Made up of two half cells connected with wires and porous salt bridge
Define fuel cell
- are a type of galvanic cell that converts chemical into electrical via a constant supply of reactants
- Oxygen is always at the cathode
Electrode property:
1. porous electrodes
2. conductive electrode
3. catalytic electrodes
Fuel cell equations
The whole equation is just a combustion reaction
- Half equations will alway vary due to the electrolyte (its the way you balance them)
- O2 is at cathode
- Fuel at anode
- Balance based on electrolyte
Fuel cell ADV vs DISAD
ADV
- efficient
- continuous supply of energy
DISAD
- expensive set up cost
- requires constant supply of fuel
- Produces DC currect
- May need to be kept at high temps
CHOOE/what cell
Molten carbonate
C- balance carbon with CO2
H- Balance hydrogen with H2O
O- Balance oxygen by adding CO3 (2-) for every oxygen needed
O- Balance oxygen by adding the same number of CO2, as there is CO3 (2-) on the other side
E- Balance electrons
CHOxE/what cell
C- Balance C with CO2
H- Balance H with H2O
Ox- Balance O with O(2-)
E- balance electrons
