oxidation/reduction

Reaction of nickel with iodine

Powdered nickel and powdered iodine are mixed together. Adding drops of water to the mixture fails to initiate a reaction.

Zinc iodine reaction

Powdered zinc and solid iodine are mixed and no reaction is observed. Adding water to the mixture initiates a reaction.

Aluminum iodine reaction

Powdered aluminum and solid iodine are mixed and no reaction is observed. Adding water to the mixture initiates a reaction.

Oxidation and reduction of copper

A piece of copper metal is heated in a flame and oxidized to black copper oxide by air. The oxidized copper is reduced when placed in a hydrogen atmosphere. When removed from the hydrogen atmosphere, the metal is again oxidized.