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
This demo makes use of the catalytic decomposition of hydrogen peroxide to produce a column of steam out of a flask, that looks like a genie coming out of a bottle.
2H2O2 → 2H2O + O2, KI is a catalyst
Hydrogen peroxide is decomposed quickly in liquid soap with the help of a catalyst to create a large volume of foam that grows out of a graduated cylinder. The soap bubbles contain oxygen.
2H2O2 → 2H2O + O2, KI is a catalyst