DESCRIPTION:
This is a very exciting exothermic reaction that produces a flame and a lot of smoke.
Zn + NH4NO3 → N2 + ZnO + 2 H2O, NaCl is a catalyst
TOPICS COVERED:
– exothermic reactions
– redox
– catalysis
– chemical change
MATERIALS NEEDED:
– 1 g zinc dust
– 1 g NH4NO3
– 0.25 g NaCl
– large beaker with a glass dish to cover it
– watch glass
– dropper with water
PROCEDURE:
1. place the zinc, ammonium nitrate and salt in the watch glass and blend carefully
2. place the watch glass in a large beaker
2. make a mound out of the powder and make a small divot in it
3. add a drop of water into the divot
4. cover the beaker to contain the smoke
ADDITIONAL COMMENTS:
This reaction happens very rapidly! Also, the clean up takes awhile. HCl is useful to dissolve the ZnO residue on the glassware, as it is not water soluble.
SAFETY:
This reaction should be done in a fume hood. Goggles should be worn at all times. This reaction happens very rapidly and is very exothermic. The zinc and ammonium nitrate mixture can ignite from the water in the air, so caution should be taken when mixing them. All products can be washed down the drain when finished.
REFERENCES:
Shakhashiri, B.Z. Chemical Demonstrations; University of Wisconsin Press: Madison, 1983; Vol. 1, pp 51-52.