D-2 STOICHIOMETRY
MAKING COPPER
A. INTRODUCTION:
Iron will replace copper in a solution of copper (II) sulfate. However, there is more than possible reaction:
Copper (II) sulfate (aq) + iron (s) → copper (s) + iron (II) sulfate (aq)
Copper (II) sulfate (aq) + iron (s) → copper (s) + iron (III) sulfate (aq)
In this lab, you will measure the amount of product formed when measured amounts of reactants are mixed. From
this information, you will determine which equation applies to the reaction you run in the experiment.
BEFORE YOU BEGIN
⇓
SAFETY AND WASTE DISPOSAL
1. Safety goggles need to be worn in this lab
3. Dispose of all wastes as directed by the instructor.
EQUIPMENT
Goggles, three beakers, ring stand, ring, wire gauze, Bunsen burner, balance, stirring rod
MATERIALS
CuSO4 - anhydrous (s), iron filings (s), Distilled water
B. Procedure
1.
Clean and dry the 250 ml beaker
2.
Weigh 12.00 g of copper (II) sulfate pentahydrate in a beaker (this is the
anhydrous form)
3.
Add approximately 50 ml distilled water to the beaker
4.
Arrange the beaker and ring stand as shown. Carefully heat and stir the
mixture in the beaker. The solution should be hot, but not boiling. After
all of the crystals have dissolved, turn off your burner.
5.
Add 2.0 grams of iron filings SLOWLY to the hot copper sulfate solution
while stirring – make sure to rinse the sides of the beaker and stirring
rod SPARRINGLY. Record your observations
6.
Allow the beaker to cool for 10 minutes
7.
Mass a piece of filter paper, label your initials and hour in
PENCIL.
8.
Filter the copper through the filter paper (as shown),
making sure to rinse the beaker of all copper. Rinse the
cooper gently twice. The filtrate can be poured down the
sink.
9.
Obtain a clean, dry small beaker; label your initials and
hour with the marking tape. Get the mass.
10. Carefully transfer the filter paper and copper into the
massed & labeled beaker. Heat overnight in oven
Next day: Weigh the filter paper, copper, and beaker on the
centigram balance--record. Clean all glassware.
D-2 STOICHIOMETRY
MAKING COPPER
C. DATA
A - Mass of beaker
A - ___________
B – Mass of CuSO4●5H20 used
B - ___________
C – Mass of Fe used
C - ___________
D - Mass of filter paper
D - ___________
E - Mass of beaker, filter paper, and copper
E - ___________
F - Experimental mass copper produced
F - ___________
G - Describe any observations you made during the reaction:
D. QUESTIONS
1. Write a balanced equation for each possible reaction.
2. Which reactant is limiting? Use the chemical equations, stoichiometry AND your observations.
3. Calculate the theoretical mass of copper produced:
If iron (II) sulfate ___________
If iron (III) sulfate ___________
4. Calculate the percentage error:
If iron (II) sulfate ___________
If iron (III) sulfate ___________
5. What is the formula for the iron-containing compound that is formed when copper (II) sulfate and iron react? How
do you know?
6. Why were the amounts chosen so this reactant was limiting? What would be a problem with having the other
reactant as limiting?
7. Were there any observations you made that support the idea that a chemical reaction has occurred? Explain.
8. Why didn’t the water added to the copper (II) sulfate have to be measured exactly?
Adapted from: Zumdahl, et al. World of Chemistry. Houghton Mifflin, Boston; 2002.