Copper Cycle Lab
Introduction
Chemical reactions are often
accompanied by formation of a precipitate, evolution of
gas, change in color, or pronounced temperature change.
In this activity, you will observe these characteristics of chemical reactions. Enjoy the variety!
9.
Purpose
To recognize that change of state, change in color, formation of a precipitate,
or the evolution of heat are associated with a chemical change; to study
reactions of copper.
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11.
General Safety
Considerations
Wear protective glasses and an apron at all times.
Procedure
Avoid skin contact with solids and solutions. Dispose of all solutions in the
containers provided by Mr. Crider. Wash your hands before leaving the
laboratory.
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Add a precut piece of aluminum wire to the test tube. This reaction is very fast! (Instead, Mr.
Crider may tell you to run cold water over the outside of the test tube. Be sure to use a test
tube holder to hold the test tube since the reaction gives off considerable heat.) The products
forming in this step are hydrogen gas, H2(g), aluminum chloride solution, AlCl3(aq), and
metallic copper, Cu(s).
When reaction is finished (stops bubbling and liquid is clear) discard the liquid into the flask.
Wash the solid in the test tube with distilled water. Fold the fPour the test tube contents into
filter paper.
Use tweezers to remove any leftover pieces of aluminum wire. Observe the final product.
END OF DAY 2
Take the filter paper with your product to the fume hood. Mr. Crider will test a small sample
of your product with concentrated nitric acid.
Clean pipets, test tube, and funnel.
Wash hands thoroughly before leaving the laboratory.
END OF DAY 3
First, prepare a data table. Record what you see throughout the laboratory
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activity.
Data Analysis and Concept Development
1. Mr. Crider will demonstrate for the class the reaction of metallic
copper with concentrated nitric acid, HNO3. This must be done in the
1. Use your observations to complete a drawing similar to
fume hood. (Caution: Avoid breathing poisonous gases. Avoid contact
the one to your left. Alongside each arrow, write in the
of skin with nitric acid. It burns skin and clothing.) One student will
chemicals used. Also near each arrow, write in key
Cu
CuCl
2
be asked to feel the side of the demonstration beaker and report to the
words to convey what you saw.
(solid)
group. The products formed are copper(II) nitrate solution,
2. As chemical changes occurred, what observations did
Cu(NO3)2(aq), and nitrogen dioxide gas, NO2(g).
you note? List the observations that alerted you that
2. A solution of copper(II) nitrate was prepared earlier. One of your thinsome type of chemical change was occurring.
stem pipets contains this solution. Transfer all of the solution to your
3. Did each reaction show all of the kinds of changes you
labeled test tube.
listed above? Use your observations to justify your
3. Another thin-stem pipet contains sodium hydroxide solution,
answer.
NaOH(aq). (Caution: Avoid contact with sodium hydroxide; it burns CuO
4. What happened to the hydrogen gas generated in the
skin.) Add this slowly to the test tube. This reaction may give off heat.
Cu(NO3)2
last reaction? Add hydrogen gas to the cycle.
(In other words, it may be exothermic.)
5. What happened to the aluminum chloride? Show this
4. Tap the tube firmly to mix or use a stirring rod.
on the cycle.
5. Add about 1/3 of a pipet of distilled water. Tap or stir to mix. The
6. What did you enjoy most about this activity?
Cu(OH)
2
solid material is copper(II) hydroxide, Cu(OH)2(s).
6. Place your test tube in a hot water bath. Remove the test tube when
you see no further change occurring. This product is copper(II) oxide,
CuO(s). Run cold water over the outside of the test tube to cool it.
END OF DAY 1
7. You will bring you test tube to Mr. Crider. He will use the centrifuge
Implication and Applications
to spin down your the solution (most dense to the bottom. Decant
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(pour out) the clear liquid (supernatant liquid) above the copper (II)
oxide into your Erlenmeyer Flash. Do not remove any of the solid.
1. Reread the title of this laboratory activity. Why is this series of reactions often called the
8. To the precipitate, add hydrochloric acid, HCl, from the final thin“copper cycle”?
stem pipet. (Caution: Avoid contact of both skin and clothing with
2. How did the last part of the procedure (Steo 16) complete the cycle?
hydrochloric acid.) Use the stirring rod to mix this until the precipitate
3. Recycling is one important way to conserve precious natural resources.
is gone. This new product is copper(II) chloride solution, CuCl2(aq).
a) What common metals have you observed being collected for recycling?
b) Think about all types of materials that you know are recycled. Compose a list of the
materials.
c) What types of materials might prove too difficult or costly to recycle?