If 350 grams of pure fe2o3 is used, how grams of can be produced? the reaction is: fe2+3c---2fe+3co
DON'T USE all lower case for chemical symbols.
CO is carbon monoxide.
Co is cobalt.
co is the abbreviation for company. It doesn't tell us a thing.
And I don't like Fe2 either. I assume you were in such a hurry you omitted the rest of the formula of Fe2O3. Finally, you didn't write WHAT you wanted; I assume another case of hurry up hurry up.
Fe2O3 + 3C ==> 2Fe + 3CO
mols Fe2O3 = grams/molar mass = ?
Use the coefficients in the balanced equation to convert mols of Fe2O3 to mols of whatever it is you want.
Then grams of what you want is mols of what you want x molar mass of what you want.