Intro to Electrochemistry Flashcards
(28 cards)
Oxidation-reduction reactions are characterized by:
the transfer of electrons between reactants.
In redox reactions, there are two:
half reactions
In redox reactions, elements either give or accept:
electrons
Redox reactions is the sum of an
oxidation and reduction reactions
Elements normally gain or loose electrons according to:
the octet rule.
The oxidation reaction correspond to
the loss of one or more electrons
The loss of electrons generates a positive charge and corresponds to an increase of
the oxidation number of the oxidized species.
causes the oxidation of another species by accepting electrons from it. It is itself
reduced in the process.
An oxidizing agent
Oxidizing agents are species with high
electronegativity
The reduction reaction correspond to
the gain of one or more electrons
The gain of electrons generates a negative charge and corresponds to
a decrease of the oxidation number of the reduced species.
gives electrons to another species and is itself oxidized.
A reducing agent (or reductant)
Every elements have a different relative
oxidizing and reducing power
The higher the standard
reduction potential EoRED
the more oxidizing the species (easier to reduce).
The lower the standard reduction potential EoRED
the more reducing the species (easier to oxidize).
Any couple which is more oxidizing than H2/H+ (take electrons from H2) has a
positive redox potential.
Any couple which is more reducing than H2/H+ (give electrons to H+) will have a
negative redox potential
Attracts electrons more strongly & Easier to reduce
stronger oxidizing agent
an element might be oxidized or the reduced, depending on the relative
oxidizing power of the element to which it is exposed
Elements can switch from the oxidized to the reduced species
as they lose or gain electrons
The oxidizing power of species is determined by its
standard reduction potential EoRED
SHE
standard hydrogen electrode
The reduction potential is related to
the driving force of a redox reaction.
If a species very willing to give off its electron (strong reducing agent) is combined
with a species very willing to accept electron (strong oxidizing agent) the reaction
will occur
spontaneously
