LIMITING REACTANT LAB
PURPOSE: To determine the limiting reactant for a specific reaction in which amounts of reactants are
carefully measured.
Be sure to record all data, color changes, and observations in your lab book.
MATERIALS & PROCEDURE:
1. Get a 400 mL beaker, fill it with water and heat it to a boil on a hot plate. Put a boiling chip in the
water.
2. Weigh out 0.50 grams of Copper (II) Sulfate and add it to a test tube.
3. Add 15 ml of distilled water to the test tube and shake to mix the solution.
4. Obtain a piece of aluminum foil that has an area of approximately 50 cm2. Record the mass of the foil.
5. Lightly wrap the foil around a glass rod. Put the foil tube into the test tube with your solution.
6. Place the test tube in the boiling water bath. Heat the test tube for 10 minutes.
7. Carefully remove the foil from the test tube and record observations about the foil’s appearance and
color of the solution
8. Carefully, rinse all particles off of the remaining foil with water. Dry the foil carefully and completely
with a paper towel and record its mass.
9. Clean all glassware and put everything back where it belongs.
DATA & OBSERVATIONS:
Make a data table and record important measurements & observations.
CALCULATIONS AND QUESTIONS (in your lab notebook)
Note: the Copper (II) Sulfate was actually hydrated with 5 water molecules and has a molecular weight of
249.70 g/mol. For our purposes, use this molecular weight when trying to determine the moles of Copper II)
Sulfate.
1. What does the color change indicate?
2. What does the aluminum look like at the end of the lab (look closely)? From a chemical perspective,
why did this happen?
3. Based on your observations during the lab, identify the limiting reactant and the excess reactant.
Explain your choices.
4. What is the identity of the brown solid that formed?
5. Write the balanced equation for the reaction.
6. Using the amounts of aluminum and copper (II) sulfate you added together, use stoichiometry to
determine the limiting and excess reactants.
7. Based on your answer to #6, calculate how many grams of aluminum should have reacted in this
experiment.
8. Using your data, calculate the mass of aluminum which actually reacted. This is simply a subtraction.
9. Calculate your percent yield.
CONCLUSION:
Write a conclusion that explains how you can identify a limiting reactant using calculations and report your
percent yield.