If 5.6 mol of CuCl2 reacts with 10.2 mol of NaNo3, what is the limiting reagent?
Here's the chemical equation, but you need to balance it still:
CuCl2 + NaNO3 => Cu(NO3)2 + NaCl
The reactant that produces the lesser amount of product is the limiting reagent.
Here's an example problem:
http://www.chem.tamu.edu/class/majors/tutorialnotefiles/limiting.htm