( Athen Id 1
AN IMPROVED THERMITE DEMONSTRATION
Submitted by: Leonard I . Kindler, J.H.S. 192, St. Albans,
N.Y.
Checked by: Willard D. Houston, Ravenna High School, Ravenna, Ohio PREPARATION Provide a piece of brass tubing of 1-in. id, 1.25 in. long and open at both ends, filter paper, dry sand (molder's sand is especially suitable), a metal tray or asbestos square, and Thermite mixture with the usual igniting chemicals. Line the tube with a single layer of filter paper, folded over at the bottom to form a cup. DEMONSTRATION Place the tube vertically on top of a pile of dry sand a t least two inches deep. (The metal tray is convenient for transporting the sand after the reaction.) Fill the tube with Thermite mixture and ignite in the usual way. The iron which is formed collects as a compact button, and may be picked up with crucible tongs and exhibited while still white hot. The button may be used for demonstrating the ferromagnetism of the product.
REMARKS This method reduces the explosion hazard encountered with the usual ceramic crucible, which is subject to dampness. In case the Thermite fails to ignite, the contents of the brass tube are easily dumped by tipping the tube, and this may be done from a considerable distance. REFERENCES
ARTHUR,P., "Lecture Demonstrations in General Chemistry," McGraw-Hill Book Co , New York, 1939, p. 362. ALYEA,H., AND DUTTON,F., "Tested Demonstrations in Chemistry," 5th ed., Chemical Education Publishing Co., Easton, Pennsylvania, 1962, pp. 17, 80, 95. and 168. Journal of Chemical Education
August 1966
RATES OF REACTION Submitted by: Alfred W. Sangster, University of the West Indies, Jamaica Checked by: David B. Moss, Hiram College, Hiram, Ohio
PREPARATION Provide three 100-ml flat bottomed flasks with rims, balloons, zinc dust, copper sulfate crystals, and dilute (3 N) sulfuric acid. Place 3 g of zinc dust and a crystal of copper sulfate in each flask. Prepare three sulfunc acid solutions:
( A ) 20 ml of dilute sulfuric acid (3 N). (B) 20 ml of 3 N sulfuric acid & 20 ml of water. (C) 20 ml of 3 N sulfuric acid & 60 ml of water. DEMONSTRATION Add the solutions of sulfuric acid to the three flasks
in the order, C, B, A , quickly covering the top of each flask with a balloon as soon as the acid is added. Observe the rate of filling of the balloons (1) Comment on the rate of filling of the balloons. (2) Calculate the volume of hydrogen expected in each case. (3) What will be expected upon long standing? REMARKS
The quantities of material may be scaled up, but not so far that the balloons might burst.
r n a l of Chemical Educai-mn
August
1966
