Name ________________________________________
Block _______
Date _______________
Lab #13: Extracting Copper
Objectives: The purpose of this lab is to apply stoichiometry to carry out and evaluate a chemical reaction.
Introduction: Metallic zinc will react with copper (II) sulfate solution according to the following equation.
Zn(s)
zinc
+

CuSO4(aq)
copper (II) sulfate
(blue)
ZnSO4(aq)
zinc (II) sulfate
(colorless)
+
Cu(s)
copper
To carry out the reaction, you will first make a copper sulfate solution by dissolving copper sulfate
pentahydrate crystals in hot water. You will then add the zinc to the solution and the reaction will begin.
Unfortunately, some of the copper that is produced reacts with oxygen that is dissolved in the solution.
2Cu(s) + O2(aq)  2CuO(s)
In other words, the products of your reaction will actually be solid cooper (the desired product), solid copper
(II) oxide (an undesired byproduct), and dissolved zinc sulfate (the other product of the replacement reaction).
The metallic copper must be purified (i.e. separated from the other substances) before it is weighed. To do
this, we treat the product with hydrochloric acid. This reacts with and removes the copper (II) oxide. The
product is also washed with water several times. This removes any dissolved zinc sulfate that is trapped
between the copper particles.
Materials:
Goggles
100-mL beaker (2)
Wash bottle with water
Ring stand/burner/tubing/striker/ring/wire gauze or
hotplate
Electronic balance (0.01 g)
Graduated cylinder (100-mL)
3M Hydrochloric acid
Zinc, granular solid
Copper sulfate pentahydrate, CuSO4•5H2O
Filter paper
Glass stirring rod
Glass funnel
Thermal gloves
Safety: Copper )II) sulfate is a skin and respiratory irritant. It is toxic by ingestion and inhalation. Avoid
shaking the container, which may produce an airborne dust of the material. Concentrated hydrochloric acid is
extremely corrosive and is very harmful to the skin and eyes. Avoid skin contact at all times. If you
accidentally spill any on yourself, flush the area with water immediately and alert your instructor. Wear
goggles at all times. Be sure to wash your hands thoroughly at the end of the experiment.
Pre-Lab: In this experiment, you will use 12.00 grams of copper (II) sulfate pentahydrate (CuSO4•5H2O).
1. Use stoichiometry to determine how much zinc you will need to use to completely react with copper(II)
sulfate. (see steps below)
a)
b)
c)
d)
Determine the number of moles of CuSO4•5H2O you will be using.
How many moles of CuSO4 are in this many moles of CuSO4•5H2O?
Calculate the moles of zinc you will need to completely react with the CuSO4.
Calculate the mass of zinc (in grams) you will need to weigh out.
2. Calculate the mass of metallic copper you should expect to get in this experiment (i.e. the theoretical yield
of copper)
Procedure: Extraction of Copper
1. Weigh out exactly 12.00 grams of CuSO4•5H2O into a clean, dry 100-mL
beaker.
2. Using the graduated cylinder, measure out approximately 50 mL of water
and add it to the beaker containing CuSO4•5H2O.
3. Weigh out the mass of zinc that you calculated in the Pre-Lab into a cup
or weighing dish. Record your observations of the solid. Set aside.
4. Set up the heating apparatus shown below.
5. GENTLY heat the beaker of copper sulfate and water and stir with a glass stirring rod until all of the blue
solid dissolves. (Do NOT boil the solution).
6. When all the crystals are dissolved, stop heating. Remove the beaker from the heat, and record your
observations of the solution.
7. While stirring, SLOWLY add the zinc to the copper sulfate solution.
8. When all the zinc has been added, continue to stir for 5 more minutes
9. When the 5 minute reaction time is up, record your observations of reaction mixture.
Procedure: Purification of Copper
Decanting is the process of carefully pouring off the liquid portion of the mixture, while
leaving the solid at the bottom of the original container. A stirring rod is placed into the
new container to direct the flow of the liquid and prevent splashing. (See diagram to
left).
10. Decant the liquid from your reaction mixture into the 250 mL beaker, leaving the
metallic copper behind.
11. CAUTION: Hydrochloric acid is extremely corrosive. In the hood, use a plastic
pipet to measure out about 10-mL of 3 M hydrochloric acid into the 10-mL
graduated cylinder. While in the hood, SLOWLY add the acid to the copper in the
beaker.
12. Stir for 5 minutes and record any observations of the solution.
Fine particles or particles that settle slowly are often separated from a liquid by
filtration.
13. Find and record the mass of a piece of filter paper. Write your group number and
block number in pencil on the edge of the filter paper.
14. Fold a circular piece of filter paper along its diameter, and then fold it again to form
a quadrant. See the diagram to the right. Separate the folds of the filter, with three
thicknesses on one side and one on the other. Support a funnel on a small ring stand as shown to the right.
15. Wet the funnel with your wash bottle before the paper is added. Then insert the filter paper into the funnel
and press the edges of the filter paper firmly against the sides of the funnel so no air can get between the
funnel and the filter paper while the liquid is being filtered.
16. Place a beaker under the funnel to collect the filtrate (the liquid that passes through the filter). Adjust the
funnel so that the stem of the funnel just touches the inside wall of the beaker. Remember that the filtrate
will be VERY ACIDIC due to the hydrochloric acid added.
17. Empty the contents of your 100-mL beaker into the funnel, never letting the liquid flow over the top of the
filter paper. Try to keep the liquid flowing through the funnel in order to avoid air bubbles.
18. Using the wash bottle, rinse the beaker until all of the copper particles have been transferred to the filter
paper. Then wash the solid copper in the filter paper three times with water from the wash bottle, waiting
for the water to pass through in between each washing. This should remove any salt solution from the
copper. Also, wash the filter paper to remove any hydrochloric acid that may be left on the paper.
19. Carefully remove the filter paper from the funnel. Open it up so that it will dry and place it a location
where it will not be disturbed.
20. When the copper and filter paper have dried, record the mass of the copper + filter paper. Examine the
solid and record your observations.
Clean up and disposal:


Wipe up any spills with wet paper towels and dispose of them in the trash. Clean all equipment.
Dispose of the filtrate in the designated area.
Calculations:
1. Determine your actual yield of copper from your data.
2. Determine your percent yield using the theoretical yield you calculated in Pre-Lab #2.
Analysis:
1. Classify the type and subtype of reaction in this experiment?
2. What evidence indicates that a chemical reaction occurred (e.g. GOPEC)?
3. Does this reaction agree with what you could have predicted using the Activity Series on your Chemistry
Reference Tables? Explain.
4. Discuss at least two reasons that may account for why your percent yield did not equal 100%. For each,
suggest a specific action that can be taken to reduce or avoid the source of error if the experiment were
repeated.
5. An alternate name for this lab is “Turning Zinc into Copper.” Why is this title misleading? Suggest a
more accurate name for the lab.
Extension:

Suggest one test that would prove that the material you obtained in this experiment is actually metallic
copper. Be sure to include what results one would expect. (Hint: Think of physical and chemical
properties of copper. If you can’t think of anything, you will need to do some research).