Chemistry
posted by K .
Iron is obtained from iron ore according to the following reaction: Fe2O3+CO> Fe+CO2 (unbalanced).
a. Assuming the blast furnace is 90.0% efficient in recovering the iron, what is the actual mass of iron obtainable from a ton of ore?
b. What is theoretical yield of iron if 200.0g of Fe2O3 reacts with 100.0g of CO?
c. How many grams of excess reactant are left at the end of the reaction?

Here is a solved example of a stoichiometry problem. It will work a.
For b, this is a limiting regent problem. I work this type by doing two of the simple stoichiometry problems and using the reagent that produces the smallest value for moles of the product.
c is same type as a. 

Thank you.