Answer: The mole ratio determines which reactant ‘limits’ how much product can be used. The reactant that produces the least amount of reactant is the limiting reactant.
Explanation: For example, say 2 graham crackers + 1 marshmallow + 4 chocolate pieces = 1 smore.
If you had 17 GC, 7M, and 20 CP....
17GC/2GC= 8SM, 7M/1M= 7SM, 20CP/4CP= 5SM. So chocolate pieces are the limiting reactant in this case because they produce the least amount or yield, or s’mores.