The first step of the synthesis is described by the reaction below. When 1.200 g of Fe(NH4)2(SO4)2 6H2O is mixed with 13 mL of 1.0 M H2C2O4 , the theoretical yield of FeC2O42H2O is

grams.

Fe(NH4)2(SO4)26H2O(s) + H2C2O4(aq)->
FeC2O42H2O(s) + (NH4)2SO4(aq) + H2SO4(aq) + 4 H2O(l)

i don't know how to approach this problem.

This is a limiting reagent problem with H2C2O4 NOT the limiting reagent. The other one is. Then a regular stoichiometry problem. If you get stuck explain exactly what the problem is.