U5|Electrochemistry - section 19 Flashcards
What is reduction?
GER
- gain of electrons
What is electrochemistry?
study of the interchange of chemical energy and electrical energy
what is oxidation?
LEO
- loss of electrons
What is an oxidation state?
the (imaginary) charge the atom would have if all the valence electrons in bonds are assigned to more electronegative atom in a mole or ion
What is the oxidizing agent?
- the species that gains e- is reduced
- called the oxidizing agent because it makes it possible for the other species to be oxidized
What is the reducing agent?
- the species that loses e- is being oxidized
- called the reducing agent because it makes it possible for the other species to be reduced
Predicting Redox reactions
- List all possible reduction and oxidation species
- determine which species will be reduced (OA) and which species will be oxidized (RA)
- choose reaction with the highest standard reduction potential -> SOA
- consider that the more electronegative element is more likely to be reduced
- choose reaction with the lowest standard reduction potential -> SRA - write own the half reactions
- balance and combine half rxns (by canceling out the electrons)
voltaic (galvanic) cell
- with salt bridge
- spontaneous
- chemical energy -> electrical energy
G<0
Ecell > 0
Electrolytic cell
- non-spontaneous
- electrical energy -> chemical energy
G>0
Ecell<0
What happens in the cathode?
reduction
What happens in the anode?
oxidation
Cations migrate to the ___
cathode
Anions migrate to the ___
anode
cell diagram and the cell notation
anode on the left separated by state boundary
cathode on the right separated by a states boundary
both are separated with salt bridge || half-cell compartment
when Ecell>0
rxn is written is spontaneous
