Name ________________________
Date ___________ Hour __________
Section 12.3 Guided Reading
1. Why do reactions stop?
2. Define limiting and excess reactants.
3. What is the limiting tool in the example given in the
book?
4. What must first be done to the masses given in a
limiting reactant problem?
5. Should you use the amount of the limiting or excess
reactant to calculate the amount of product produced?
Why?
6. Why use an excess of any reactant in a chemical
reaction?
Try this problem now.
The reaction between solid sodium and iron (III) oxide is
one in a series of reactions that inflates an automobile
bag.
6Na + Fe2O3  3Na2O + 2Fe
if 100.0 g Na and 100.0 g Fe2O3 are used in this reaction,
determine
a.
b.
c.
d.
the limiting reactant
the reactant in excess
the mass of solid iron produced
the mass of excess reactant that remains after the
reaction is complete.