Shockingly Brief yet Rich History of electrochemistry

•Galvani – frog legs~1780

• Volta – battery~1800

•Davy- electrolysis~1820

Chemistry born from dead frogs

Luigi Galvani nasce a Bologna nel 1737.

Physiologist noticed legs of dead frogs twitched when his steel scalpel touched brass staples used pin down frog legs

Galvani thought he discovered animal electricity,

but he just found a delectable appetizer!

Allessandro Volta (volt)

• Didn’t buy Galvani’s explanation

• Enjoying sticking 2 metals on his tongue, and got same twitching as frog legs

• Invented the “pile”, a.k.a battery:

More layers could be “piled” on to get higher voltages & currents

Volta’s pile ~ same 200 yrs later!

Zn anode oxidation (-) Cu cathode reduction (+)

Electrochemistry under the hood

Making a battery work:Pick 2 different metals

Standard Reduction Potential (Eo):- The metal that will act as the cathode, be

reduced, gain electrons has the most positive potential (electrons flow to +)Ag+ Eo= +.80

Cu++ Eo= +.34

Zn++ Eo= -.76

Al+++ Eo= -1.7

Example: Cu|Zn has Eo = 1.1V (zinc is oxidized so it’s Eo sign is reversed)

Electrons flow from negative Cu anode to positive Zn cathode

Davy- cocky inventor of electrolysis

Sir Humphry Davy

Detested Gravy

He lived in the odium

there he discovered sodium

Only scientist besides Newton to be knighted

Contemporary of Volta, Ampere, Gay-Lusaac, assistant was Faraday

Discovered many elements(Na,Ca,Mg,K,Ba,Sr) arc lamps, laughing gas (N2O), water electrolysis, showed oxidation need not oxygen,CO2

Electrolysis- Davy’s Domain

Volta – 2 different metals produces currentDavy - chemical reactions produce current

Electrolysis- use a battery to drive & even reverse reactions! * almost any compound can be oxidized or

reduced using the right voltage!

Electrolytic cell

• non-spontaneous reactions (negative total potential) are possible using a battery

• Negative end of battery provides electrons so reduction can occur at the cathode (-)