The document discusses electrochemistry concepts including oxidation-reduction reactions, electrical chemical cells, galvanic cells, standard cell notation, standard cells, and the Nerst equation. Key points include: redox reactions involve separate oxidation and reduction half reactions; cells split these half reactions between an anode and cathode connected by a salt bridge; cell potential is measured in volts and relates to Gibbs free energy; and the Nerst equation allows predicting non-standard cell potentials based on reaction quotient concentrations.
2. Electrochemistry
Oxidation Reduction chemistry (Electron Transfer)
Remember RedOx reactions must be balanced as two
separate reactions, the
Oxidation half reaction and the Reduction half reaction
Oxidation- involves the loss of an electron : Oil
Reduction- involves the gain of an electron: Rig
3. Electrical Chemical Cells
Are split up to do the half reactions separately: an anode and a
cathode
The anode handles the oxidation
The cathode handles the reduction
Electrons flow from the anode to the cathode
The two half reactions are connected by the wire to allow the
electrons to flow and by a salt bridge
The salt bridge prevents the build up of charge that would happen by
the flow of electrons to the cathode
Cations from the salt bridge will flow into the cathode to dissipate the electron
charge build up from the presence of extra electrons in the cathode
Anions from the salt bridge will flow into the anode to dissipate the electron
charge build up from the absence of extra electrons in the anode
4. Galvonic cell / Voltaic Cell
It does the work and produces energy
Cell potential – electro motive force
Electrical potential is measured in Volts, V
It is related in dG
5. Electrical Cell notation
/ Anode / Cathode
Metal connected to Anode | Anode reaction || Cathode reaction | Metal connect to Cathode
| = phase transition
|| = salt bridge
, = used to separate aqueous components
e.g.
Pt(s) | Fe2+(aq)(.1M),Fe3+(aq)(.2M) || Cu2+(aq) (.1M) | Cu(s)
6. Standard Cells
All solutes at 1.0 M concentration
All gases at 1 atm
All solids present in pure form
All standard potentials are based of off an electrical cell paired with Hydrogen
Eocell (in volts)= Eocathode – Eoanode
Eocell , Eocathode, and Eoanode are all written as reduction potentials
Use to predict Eocell
Used to predict spontaneously, if it was is a negative E then the reaction would happen in
the opposite direction
Oxidizing agents: the agent is reduced, the strongest oxidizing agents have the highest
reduction potentials
Reducing agents: the agent is oxidized, the strongest reducing agents have the lowest
reduction potentials
7. Electrical Work
Electrical work = charge * potential difference
Joules = coulombs * volts
Faraday constant, F, the magnitude of charge on one
mole of electrons
F= 9.65 *104 C/mol electron
w=-F * potential difference
wmax=-nFEcell
Because wmax=dG
dG=-nFEcell