Review Questions:
1. BALANCE the equation first.
FeCl3 + O2
→ Fe2O3 + Cl2
a. How many moles of chlorine gas can be produced if 4 moles of FeCl3 react with 4 moles of O2?
Answer
? mol Cl2 = 4 mol FeCl3 (6 mol Cl2 / 4 mol FeCl3) = 6 mol Cl2
? mol Cl2 = 4 mol O2 (6 mol Cl2 / 3 mol O2) = 8 mol Cl2
b. What is the limiting reactant?
Answer
FeCl3
c. What is the excess reactant?
Answer
O2
2. Use the following BALANCED equation.
2 C2H6 + 7 O2 → 4 CO2 + 6 H2O
a. If 15 g of C2H6 react with 45 g of O2, how many grams of water will be produced?
Answer
? g H2O = 15 g C2H6 (1 mol C2H6 / 30.0 g C2H6) x (6 mol H2O / 2 mol C2H6) x (18.0 g H2O / 1 mol H2O) = 27 g H2O
? g H2O = 45 g O2 (1 mol O2 / 32.0 g O2 ) x (6 mol H2O / 7 mol O2 ) x (18.0 g H2O / 1 mol H2O ) = 22 g H2O
b. What is the limiting reactant?
Answer
O2
c. What is the excess reactant?
Answer
C2H6