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Demonstrations ›Chemical Reactions II

Lecture Demonstrations

Chemical Reactions II: Oxidation/Reduction

Oxidation and reduction reactions are demonstrated using one or more of the following common reactions involving copper in zinc chloride, zinc in copper sulfate, and copper in silver nitrate.

 

Observation of the oxidation of zinc metal by hydrochloric acid to form hydrogen gas and zinc chloride.

 

A flask containing a colorless solution is shaken and the solution turns blue. Upon standing the solution becomes colorless again. More shaking regenerates the color.

 

A piece of copper foil is suspended above a container containing acetone. The copper wire will continue to glow red hot suspended above the liquid.

 

Oxidation of sugar or a Gummi bear by potassium chlorate. This demonstration illustrates the amount of energy available in carbohydrates, such as sugar and candy.

 

When a ball of aluminum foil is placed in a copper solution with chloride ions, the copper ions are reduced to copper metal and a coating of copper is seen on the surface of the aluminum.

 

Primary and secondary alcohols are oxidized by K2Cr2O7 to carboxylic acids and ketones respectively. The oxidation is physically observed by the change in color upon reduction of Cr6+ (orange) to Cr3+ (blue).

 

Video demonstrations of thermite reaction.

 

Two balloons, one filled with H2 and the other with He are ignited with a hot pin or lit splint, with different results.

 

 

A combustion reaction is demonstrated by the burning of magnesium in air, emitting a brilliant light and intense heat.

 

A piece of tarnished silver is cleaned using an aqueous solution of baking soda, salt, and aluminum foil.