PROBLEM 1: FezO3 + 3CO - 2Fe + 3CO2 In the chemical equation provided above, let us suppose that a scientist was given 30.0 grams of Fe203 and 16.80 grams of CO simultaneously. Which substance should be used completely and which substance would have an excess after reaction? Step 1. Find the amount of the reactants needed in the reaction based from given amount given in the problem. Solution A. Using the given mass of Fe;O;, find the mass of CO needed in the reaction. Mass of CO = 30.0 g Fe203 x 1.00 mole FezO,_x 3.00 moles CO x 28.0 g CO 160 g FezO3 1.00 mole FezO3 1.00 mole CO = 15.75 or 15.8 g CO NV BICOL Solution B. Using the given mass of CO, find the mass of Fe:O: needed in the reaction. purposes OI Mass of FerO: = 16.80 g CO x 1.00 mole CO x 1.00 mole Fez03 x 160 g FezO; 28.0 9 CO 33.00 moles CO 1.00 mole Fez03 = 32.0 g Fez03 Observe how solution A & B use the general formula for mas-mass calculation below. Stoichiometry Checkpoint! Mass A x Molar mass A x no. of moles B (Mole ratio from balance equation) x Molar Mass B no. of moles A