A chemical reaction is when two chemicals (reactants) form to make a new chemical substance. During the chemical reaction, the atoms are rearranged to form the aforementioned new chemical substance (products).
There are different types of chemical reactions, however, in this definition, I will not be explaining them.
Guy 3: Woah, did you see that chemical reaction?
Guy 1: Hell yeah I did!
Guy 2: I wonder if we could do it again?