Chemical reactions we are used to here on Earth are hardly possible in most of interstellar space due to extremely low temperature and density (though some pretty complex molecules are found there, that Wikipedia article listing
gas-phase ion chemistry (often driven by cosmic rays) and surface chemistry on cosmic dust
among possible formation mechanisms). On the other extreme, close to a star or other energy source, chemical reactions also make little sense because they would be overtaken by other processes with energy much higher than that of chemical bonds. This is why astronomers call all elements except hydrogen and helium metals.
Somewhere in between lies our home, where schoolchildren study all the diversity:
combination, decomposition, single-replacement, double-replacement, and combustion.
Obviously, all of these types of chemical reactions are possible on any other Earth-like planet. However, what about other types of planets?