Reactants with their products
This is an example of a decomposition chemical reaction.
2Нg(NCS)2 ---> 2HgS + C3N4 + CS2
You can visually see that when Mercury(II) thiocyanate is ignited, it completely changes, forming some sort of crazy shape. While looking at the chemical equation, you can see that the more complicated substance is being broken down.
This is also an example of a combustion chemical reaction.
(NH4)2Cr2O7 ---> Cr2O3 + N2 + 4H2O
In the experiment above, Ammonium dicromate is being lite on fire which causes it to take this volcanic form. Once you set fire to the substance, it burns in oxygen, which is why you can see the flame within the "volcano".
This is a really fun and colorful experiment. It's called Elephant toothpaste. It is also a decomposition reaction.
2H2O2 ---> 2H2O + O2
As with the other experiments, the chemical equation says it all.