For the reaction 4FeCl2(aq) + 3O2(g) - 2Fe2O3(s) + 4Cl2(g); how many grams of FeO3 are produced from 8.71 x 10 to the 21st power molecules of O2?? Help Please!

Answer 1

4FeCl2(aq) + 3O2(g) - 2Fe2O3(s) + 4Cl2(g)
mols O2 = 8.71E21 molecules x (1 mol/6.02E23 molecules) = ?
Using the coefficients in the balanced equation, convert mols O2 to mols Fe2O3
Then convert mols Fe2O3 to g Fe2O3 with g = mol Fe2O3 x molar mass Fe2O3.