CHEM: Unit 1: Electrochemistry

Redox

electron transfer reactions

Reduction

gain of electrons

Oxidation

loss of electrons

Oxidizing Agent

causes oxidation by being reduced itself

Reducing Agent

causes reduction by being oxidized itself

Cells

containers of liquid with electrodes

Electrolytic cell

Electricity is used to force chemicals to undergo a redox rxn

Galvanic cell

Electricity is produced spontaneously from a redox rxn

Battery

cells connected together

Galvanic cell set up

forces electrons through a wire to produce a current instead of releasing energy as heat

Galvanic cell items

- 2 1/2 cells

- 2 electrodes

- wires to allow flow of e-

- salt bridge

Line Notation

anode | electrolyte || electrolyte | cathode |

Anode

the electrode at which oxidation occurs

Cathode

the electrode at which reduction occurs

Cell potential

The electrical potential difference between the two half-cells

SATP

standard ambient temperature and pressure; exactly 25 degrees celsius and 1 M

Standard reduction potential

a measurement of how well a 1/2 cells can attract e-

Inert Electrode

- no rxn occurs with these electrodes but instead are the site of electron transfer

- typically used when REDOX rxn occurs entirely in the solution

Spontaneity

1. Spontaneous: greater than 0V

2. Non-spontaneous: less than 0 V

3. Equilibrium: exactly 0 V

Equilibrium

Reactants need to be replenished

Electrolytic Cell

a power source "pulls" electrons from the anode and pushes them through th cathode and the rest of the cell

Salt Bridge

used to maintain electrical neutrality inside the circuit of a galvanic cell.