It is Ammonium Dichromate, a orange red powder and it creates a volcano when fire is put in the center of the powder. The equation is (NH4)2Cr2O7 (s) → Cr2O3 (s) + N2 (g) + 4 H2O (g). It is also decomposition reaction. I know a reaction occurred because it let out heat, and light.
Cool Chemical Volcano
It is a white powder of mercury(II) thiocyanate and when ignited, it begins to rises and a dark yellow like substance. The equation is 2Hg(SCN)2 → 2HgS + CS2 + C3N4. It is a decomposition reaction. I know a reaction occurred because it releases smoke and ash.
Dry yeast mixed in water catalyst is then put into a mixture of 30% hydrogen peroxide dipped in liquid soap, which gets foamy together. The equation is 2H2O2 → 2H2O(l) + O2(g). It is a decomposition reaction. I know a reaction occurred when foam formed and heat was released.
Science Bob's Crazy Foam Experiment