ELECTROCHEMICAL CELLS

Batteries

Electrochemical cells

Terms to knowAnodeCathodeOxidationReductionSalt BridgeHalf cellCell potentialElectron flowVoltage

Batteries A battery is what you call an electrochemical

cell It consists of 2 half cells or half reactions

One half cell produces electronsOne half cell receives electronsThe flow of electrons is electricity!!!

Half Cells or half reactions Anode

Electrons are produced hereBy removing electrons from metal, positive ions

are produced in solution○ The anode becomes smaller

Oxidation is when electrons are lost.○ OIL: Oxidation is lost

Half Cells or half reactions Cathode

Electrons are received hereCations in solution receive electrons and become

metals○ The cathode grows in size

Reduction is when electrons are gained.○ RIG: Reduction is gain

Electricity is just electrons moving The electrons move from the anode to

the cathode, producing electricity. Volts are the units used to measure flow

of electricity.

Voltage You can determine the voltage by looking at the

reduction potentials for the two half reactions/cells Suppose I have a half reaction Zn Zn2+ + 2e-

Looking up the reduction potential it is -0.76But this is oxidation, so I reverse the sign, +0.76

Suppose I have the half reaction Cu2+ + 2e- CuLooking up the reduction potential it is +0.34

The voltage for this cell should be 0.76 + 0.34 = 1.10 V

The Salt Bridge The salt bridge allows ions to move into

or out of the 2 half cells in order to keep the two half cells with neutral charges.

All together now

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