8. The Electrochemical Series Flashcards
the electrochemical series shows
what is reactive and whats not
the more reactive a metal is the more it wants to
1. ____ electrons
to form a 2.____ ion
- loose
2. positive
more reactive metals have a more _____
negative standard electrode potential
the more reactive a non-metal is the more it wants to
1.____ electrons
to form a 2._____ ion
- gain
2. negative
more reactive non metals have a more _____
positive standard electrode potential
sometime the using electrode potentials to predict wether a reaction is feasible is wrong if …
- the conditions are not standard
2. the reaction kinetics are not favourable
why might the prediction be wrong if the reaction kinetics are not favourable
- the rate of reaction may be so slow that the reaction might not appear to happen
- if a reaction has a high activation energy this may stop it happening
why might the prediction be wrong if the conditions are not standard
- changing concentration or temperature of the solution can cause the electrode potential to change
why might the prediction be wrong if the conditions are not standard
e.g. zinc / copper cells
Zn(s) Zn2+(aq) + 2e- Eθ= -0.76 V
Cu2+(aq) + 2e- Cu(s) Eθ= +0.34 V
Zn(s) + Cu2+(aq) Zn2+(aq) + Cu(s)
increase conc of Zn2+
equilibrium shifts to left reducing ease of electron loss. electrode potential of Zn/Zn2+ becomes less negative and whole cell potential will be lower.
why might the prediction be wrong if the conditions are not standard
e.g. zinc / copper cells
Zn(s) Zn2+(aq) + 2e- Eθ= -0.76 V
Cu2+(aq) + 2e- Cu(s) Eθ= +0.34 V
Zn(s) + Cu2+(aq) Zn2+(aq) + Cu(s)
increase conc of Cu2+
equilibrium shifts to right increasing ease of electron gain.
electrode potential of Cu2+/Cu becomes more positive and the whole cell potential will be higher.
