REVISION ELECTROCHEMISTRY OXIDATION Oxidation is a loss of

REVISION ELECTROCHEMISTRY

OXIDATION • Oxidation is a loss of electrons • The oxidation number increases • E. g. • Electrodes where oxidation take place will reduce in mass • We write the oxidation reaction ‘upside-down’ from the table • Reducing agent ANODE The electrode where oxidation takes place

REDUCTION • Reduction is a gain of electrons • The oxidation number decreases • E. g. • Electrodes where reduction take place will increase in mass • We write the reduction reaction ‘right-way-round’ from the table • Oxidising agent CATHODE The electrode where reduction takes place

ELECTROLYTE solution/liquid/dissolved substance that conducts electricity through the movement of ions.

TABLE OF STANDARD REDUCTION POTENTIALS

STANDARD CONDITIONS •

CELL POTENTIALS •

GALVANIC CELL a cell in which chemical energy is converted into electrical energy. A galvanic (voltaic) cell has self-sustaining electrode reactions

SPONTATEOUS REACTIONS

SALT BRIDGE Its function is to maintain ELECTRICAL neutrality

CELL NOTATION • The H 2|H+ half-cell is treated just like any other half-cell. . • Cell terminals (electrodes) are written on the outside of the cell notation. • Active electrodes reducing agent | oxidised species || oxidising agent | reduced species • Inert electrodes (usually Pt or C): Pt | reducing agent | oxidised species || oxidising agent | reduced species | Pt Example: Pt | Cℓ-(aq) |Cℓ 2(g) || F 2(g) | F-(aq) | Pt

ELECTROLYTIC CELL a cell in which electrical energy is converted into chemical energy. ELECTROLYSIS The chemical process in which electrical energy is converted to chemical energy OR the use of electrical energy to produce a chemical change.

ELECTROLYTIC CELL

ELECTROPLATING

ELECTROPLATING

REFINING OF COPPER

REFINING OF COPPER

CHLOOR-ALKALI INDUSTRY

CHLOOR-ALKALI INDUSTRY

RECOVERY OF ALUMINIUM

RECOVERY OF ALUMINIUM

Oxidize Anode negative Reduce Cathode positive

Wants to oxidize ‘upside down’ Wants to reduce ‘rightside up’