Lab: Limiting Reactant and Percent Yield Student Guide
Pre-Lab Information
Purpose Explore the yield of a chemical reaction by identifying the limiting reactant, comparing the
theoretical and actual yields, and explaining the sources of error.
Time Approximately 45 minutes
Question While observing a chemical reaction, how can you tell which reactant is limiting?
Reaction The reaction of copper(II) chloride and aluminum is shown in this balanced equation:
3CuCl2 + 2Al  2AlCl3 + 3Cu
Hypothesis If a substance is the limiting reactant, then it will be fully consumed by the time the
reaction completes because it is the reactant that reacts completely and the reaction
cannot proceed further.
Summary You will react copper(II) chloride with different quantities of aluminum in two trials. You
will also calculate percent yield for Trial 2.