How can you find a limiting reactant in a reaction?
A stoichiometrically balanced equation is an absolute prerequisite.
For many reactions, the reagent in deficiency is obvious. Consider combustion reactions; here, a limited amount of hydrocarbon is combusted in an unlimited quantity of dioxygen gas.
And thus for methane, we write:
Here, of course, the reagent in deficiency is the hydrocarbon; the oxygen derives from the atmosphere. Under conditions of limited oxygen, and long chain hydrocarbon fuels, for instance in the internal combustion engine,
I presume you know how to convert mass to moles, and vice versa; if not give us a shout, and someone here will help you.