# In the reaction C_2H_4(g)+3O_2(g)->2CO_2(g)+2H_2O(g), if 2.70 mol C_2H_4 is reacted with 6.30 mol O_2, what is the limiting reagent?

Thus, 2.70 mol ethylene requires 8.10 mol dioxygen gas for complete reaction. How do I know this? I know this because of the given reaction stoichiometry. In the absence of stoichiometric oxygen, incomplete carbon combustion may occur to give $C$ (as soot), or $C \equiv O$, as oxidation products (or both), but I assume complete combustion, and only consider the reaction AS WRITTEN.