Lec 34 Electrochem Flashcards
Oxidation is what
Loss of electrons
Reductions is what
Gain of electrons
When is the oxidation number of hydrogen equal to -1 and not plus 1?
When it’s bound to a metal
LiH
NaH
What does a salt bridge do in a voltaic cell?
Maintains electro neutrality in both solutions (same number of positive and negative charges)
What happens when there is no salt bridge
Excess buildup of postive charges at anode
Excess negative charges at cathode
What is cell potential? Units?
The voltage made by a voltaic cell
Volts
What does the potential depend on
The half cell rxns
Concentrations and pressures of reactants
other physical variables like temp
What is SHE
The standard hydrogen electrode, it’s the reference point for calculating potential in a cell
It’s potential is exactly 0V
What is the anode
The thing that is oxidized (losing electrons)
What is the cathode
The thing that is reduced (gains electrons)
The one with the more positive cell potential (E)
What does a voltaic cell need to be spontaneous
Positive cell potential
What does you do to the sign of the reduction potential if something is oxidized
Flip the sign
