Name: _____________________________
Date: ______________________
Unit 1
Lab 2b: Retrieving Copper from Copper Oxide Samples
Introduction
While completing Lab 1: Copper Powder you heated metallic copper, producing a black powder,
copper(II) oxide (CuO). Because atoms are always conserved in chemical reactions, the original copper
atoms must still exist. In this investigation, you will attempt to recover those atoms of metallic copper.
PRELAB: Before starting the lab:
• Read the procedure to learn what you will need to do
• Start a prelab page in your lab notebook with the Title of lab, Purpose/Objective, and Materials
needed (noting safety precautions next to material, if necessary).
• The next heading in your prelab should be Procedure Notes – in your own words briefly
summarize the procedure.
• Data and Observations should be your next heading. Prepare a table in your lab notebook
where you can record the various masses measured in this investigation, and clearly label what
those data represent.
Procedure
Part I: Separating Copper(II) Oxide (CuO) from the Sample
Most likely, during Lab 1 – Copper Powder, not all the original copper powder reacted with oxygen gas
when you heated the copper in air. Some copper metal probably is still mixed in with the black copper(II)
oxide. The first steps in this activity involve separating this mixture into copper and copper(II) oxide. To
do this, you will add dilute hydrochloric acid (HCl) to the black powder. Copper metal does not react with
hydrochloric acid, so it will remain as a solid. The black copper(II) oxide, however, reacts with
hydrochloric acid to produce copper(II) chloride (CuCl2) and water, write this verbal chemical equation
in procedure notes:
1. Obtain your container of copper (II) oxide. Look closely at its contents. Is the material uniform
throughout? If not, why not? Record notes in observations section.
2. Transfer your copper(II)oxide into a clean, pre-weighed (record in data table) 150mL – 200mL
glass beaker.
3. Record the weight of your initial amount of copper(II)oxide powder
4. Add 40 mL of 1 M HCl to the beaker containing the copper oxide mixture. Record your observations
of the solution. (Caution: 1 M hydrochloric acid may damage your skin. If some HCl does spill on
your skin, ask another student to notify your teacher immediately. Begin rinsing the affected area
with tap water immediately.)
5. Gently heat the mixture on a hot plate on the lowest heat setting. Continue heating for 15 minutes,
stirring every few minutes with a glass rod. In the meantime, write your initials on the piece of filter
paper and measure and record the mass paper.
6. Remove the beaker from the hot plate. Turn off the hot plate. Allow any unreacted copper metal still
remaining to settle to the bottom of the beaker. Then slowly decant the liquid into a second, empty
150-mL beaker.
7. Wash the solid copper remaining in the first beaker several times by swirling it gently with
approximately 10 mL of distilled water.
8. Fold the piece of filter paper into a cone shape and place into a funnel on second beaker. Then decant
the liquid into the second beaker, adding it to the liquid you collected in Step 5. Set aside the
collected liquid contained in the second beaker (approximately 50 mL) for Part II. Using a rubber
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Name: _____________________________
Date: ______________________
policeman, scrape all the unreacted copper from the 1st beaker on the filter and then set-it out to dry
overnight on the counter.
9. In class on Monday, after the sample and filter paper have dried, find the mass of the solid copper.
This represents the portion of the original copper powder that failed to react to form CuO. Record this
mass in your laboratory notebook.
Part II: Converting Copper(II) Chloride to Copper
The final step in this investigation is to convert the dissolved copper(II) chloride (CuCl2) to copper metal.
Perhaps you already have an idea how to do this. By adding solid metal samples to solutions that contain
other metal ions, the more reactive metal will replace the less reactive metal in solution (see metal activity
series). Which of the tested metals are more active than copper? Try to predict the result of placing one of
those more active metals in your copper(II) chloride solution. Check your prediction by completing these
steps.
10. Obtain a watch glass that can completely cover the top of the beaker containing copper(II) chloride
(CuCl2) solution. Next, carefully place the zinc metal into the CuCl2 solution.
11. Immediately cover the beaker with the watch glass, and allow it to stand for several minutes. Record
your observations.
12. After the reaction has subsided, remove the watch glass and gently dislodge the solid copper that has
formed on the surfaces of the zinc pieces.
13. Continue to dislodge the copper from the zinc until you are convinced that the zinc has stopped
reacting with the solution. (How can you decide? Record notes in observations section.) Then, add 10
mL of 1 M HCl to the beaker and carefully remove any large pieces of solid zinc from the beaker
with forceps. Place used Zinc in the used zinc container located on side lab bench. Replace the watch
glass. Record your observations.
14. After a few minutes, carefully decant as much of the liquid as possible into another empty beaker.
Dump the liquid into the waste container in the hood.
15. Wash the solid copper several times with distilled water.
16. Transfer the copper to a preweighed piece of filter paper, and allow the copper to dry overnight.
17. After the sample and filter paper have dried, find the mass of copper metal. This represents the copper
that you recovered from the copper(II) chloride solution.
18. Follow your teacher’s instructions for disposing of waste materials.
19. Wash your hands thoroughly before leaving the laboratory.
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Name: _____________________________
Date: ______________________
Post Lab Questions
1. During Lab 1 Converting Copper,
a. What mass of the original powdered copper sample reacted when you heated it? (Hint: Refer to
the original mass of copper you used during this investigation and the mass of copper residue
found in Step 8 to calculate this.)
b. What percent of the total copper sample reacted?
2. How much copper wasn’t recovered from CuO product? Use your data table and show work.
3. In only the ideal circumstances, if you started with 1.00 grams of copper powder would you have
finished with 1.00 grams of copper powder. Calculate your percent yield.
Percent Yield = 100% X Actual mass of copper recovered/ starting mass of copper
4. In the reaction between copper(II) chloride solution and zinc metal, each Cu2+ ion gained two
electrons to form an atom of copper metal. Each zinc metal atom lost two electrons to form a Zn2+
ion:
a. Write a balanced chemical equation that represents this process.
b. Based on the chemical equation, what was the reactant that was oxidized? What was the reactant
that was reduced? How do you know?
5. Adding HCl to CuO, resulted in the formation of a blue solution. This color is due to the presence of
Cu2+(aq) ions. Consult your observations when answering the following questions:
a. Draw a particle level drawing (submicroscopic level) of what this solution looks like:
b. Describe what happened to the solution color after you added zinc.
c. What caused the changes you observed in the solution?
a. How can the color of the solution be used to indicate when the zinc metal has removed the
Cu2+ ions from the solution?
6. To recover Cu metal from the CuCl2 solution, you had to use other resources:
a. What resources were “used up” in this recovery process?
b. Where (to what location) did each resource finally go?
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