Jean Mason                     Maria High School
                               6727 S. California Ave.
                               Chicago, IL 60615

      To enable the student to balance oxidation-reduction reactions by using the 
half reaction method. 

      sodium metal, petri dish, distilled water, phenolpthalein, test tubes, 

      Fill a petri dish half full of distilled water. Put 2-3 drops of 
phenolpthalein and 1-2 grains of detergent in the dish. Place the dish on an 
overhead projector and add a small amount of sodium metal. Cover the dish with the 
top of the petri dish to prevent splattering on the overhead screen. Ask students 
to determine the products. If difficulty in determining the products arises, add a 
small amount of sodium to a test tube containing distilled water and 
phenolpthalein. Place a lighted splint over the mouth of the test tube as soon as 
the gas appears. Write an overall equation for the reaction then proceed to write 
half equations. Add the two half equations which gives the redox reaction. 
Additional equations should be given to the student. 

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