Electrochemical series Flashcards
What does the electrochemical series indicate?
• Indicates the strength of substances as oxidants/reductants. At the top, they are strong oxidants, and at the bottom, they are strong reductants.
How is electrochemical series linked to reactivity?
Reactivity of metals = their ability to lose electrons (ie. oxidation)
Reactivity of non metals = their ability to gain electrons (ie. reduction)
For a spontaneous redox reaction to occur:
The stronger oxidant must react with the stronger reductant. There must be one of each.
If species A is reduced and is higher on the ecs than species B that is oxidised:
Species A is a strong enough oxidant (ie. is high enough) to cause species B to be oxidised.
If species A is reduced but is lower on the ecs than species B that is oxidised:
Species A is NOT a strong enough oxidant (ie. is not high enough) to cause species B to be oxidised.
Define: potential difference
ASK
What is E*
potential difference under standard conditions (ie. standard electrode potential))
What is E
potential diffeqrence
What are standard conditions?
o 1M solution
o 25 °C
o Pressure of 1 bar (100 kPa)
How do we calculate the standard electrode potential of cells?
Connect a cell under standard conditions to a standard hydrogen electrode
Define: standard hydrogen electrode
o 1M solution
o 25 °C
o Pressure of 1 bar (100 kPa)
How to we calculate voltage/cell potential difference?
Higher e-lowerE (INCLUDE UNITS OF VOLTS (V) eg. 1.23V
If voltage is positive/negative/sero, then
spontaneous reaction did/did not occur/the cell is flat.
Limitations of the electrochemical series?
o Doesn’t predict rate of reaction
o Only applies under standard conditions: if not, the half cell potentials and order and position of half equations can change.
Define: potential difference
how much voltage is produced by the 2 half cells when connected/needed to cause a reaction
