edited - - - - - hv -, GEORGE L. GILBERT Denison University Granville. Ohio 43023
Start the Term with a Bang SueMlrrEo BY Sheldon I. Clare University 01 Pinsburgh at Johnstown Johnstown. PA 15904
CHECKED BY
Paul T. Ruda Cleveland Hills Schools Cheektowga. NY 14225 WARNING-Sodium metal reacts with violence when in contact with water or moist air. The demonstrator should w e a r protective gloves a n d eye wear. A favorite classroom demonstration of mine to begin a general chemistry course is the reaction of sodium metal with water.
This simple, but impressive, reaction illustrates chemical change nicely. This demonstration must be performed in a hood. A few drops of "magic potion" (phenolphthalein solution) are put into a 250-ml beaker containing water. A folded piece of 12.5-cm filter paper is then placed into the beaker so that only the tip of the paper touches the water (see figure). In
order to prevent the possibility of the filter paper from falling into the water, tape can be used to secure the paper to the rim of the beaker. A piece of sodium' (size of a small pea) is dropped onto the filter paper and immediately covered with a wire gauze to prevent splattering. A noise is heard which is soon accompanied by smoke rising from the beaker. The paper then bursts into flame, a small explosion is heard, and the water turns bright pink. After the demonstration, a lively discussion usually follows about how one could prove a chemical reaction has taken place. If nothing else, the demonstration starts the year off with a bang!
' If the sodium has been stored under kerosene, it should be dried
prim to the reaction, otherwise a more violeni explosion can occur. Any
excess sodium should be returned to the kerosene-containing storage bottle.
Volume 61
Number 7 July 1984
635
