Name: _____________________________________ Date: __________________ Period: _____
Evidence For A Chemical Change
Background:
One way of knowing that a chemical change has taken place is to observe that the
properties of the products are different from those of the reactants. The new
product can then become a reactant in another chemical reaction.
In this experiment, you will observe a series of chemical changes as copper(II)
nitrate is treated with a series of reactants. All of the reactions will take place in the
same test tube. As you add each reactant, you will look for evidence that a new
substance has formed as a result of a chemical reaction.
Safety Precautions:
Goggles, gloves, and aprons are required for this lab. Immediately wash any
solutions that get on your skin. Let your teacher know of any spills or broken glass
so they can be cleaned properly.
Materials:
Two 250ml beakers
Test Tube, Clamp, and Rack
Heat Source
Pipet
Glass Stirring Rod
Aluminum Foil
Copper(II) Nitrate Solution
NaOH (Sodium Hydroxide) Solutions
HCl (Hydrochloric Acid) Solution
Procedure:
1. Add 1 droppers of the blue copper(II) nitrate solution to the test tube.
2. Add 1 droppers of 1.0 M NaOH to the test tube.
3. Stir the two solutions with a stirring rod (be careful to not bust the bottom of the
test tube out with the rod). Rinse off the stirring rod before setting it down.
4. Touch the outside of the bottom of the tube and note the temperature. Is it
getting warmer or cooler?__________________
a. The copper containing product in the test tube is copper(II) hydroxide.
The other product is sodium nitrate.
Name: _____________________________________ Date: __________________ Period: _____
b. Record the changes that occur in the test tube below.
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5. Put 100ml of water into the 250ml beaker. Heat the water until it boils.
6. Place the test tube in the hot water and heat it until no more changes occur.
a. The products formed in this reaction are copper(II) oxide and water.
b. Record the changes that occur in the test tube below.
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7. Remove the test tube from the hot water and turn the heat off. Cool the test tube
and contents for 2 minutes in a second beaker of room temperature water.
8. Add 1 dropper of 1.0 M HCl to the test tube. Stir with the stirring rod.
a. The products formed in this reaction are copper(II) chloride and water.
b. Record the changes that occur in the test tube below.
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9. Place a crumpled, 1.5 square inch piece of aluminum foil in the test tube. You
may need to push it into the solution with a stirring rod. Touch the bottom of
the test tube to check for temperature changes. Is it getting warmer or cooler?
________________________
10. The reactions taking place are:
a. Copper(II) chloride and aluminum react to produce copper (the brown
product) and aluminum chloride.
b. The aluminum also reacts with leftover hydrochloric acid to produce
hydrogen gas and aluminum chloride.
Name: _____________________________________ Date: __________________ Period: _____
c. Record the changes that occur in the test tube below.
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11. Carefully remove the copper produced in the last step from the test tube onto a
piece of filter paper.
12. Compare the copper to a sample of copper wire or a new penny.
a. Record the changes that occur in the test tube below.
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13. Rinse out all glassware with lots of water and scrub the products out of the test
tube with a test tube cleaner. The solid copper may be put in the trash can. You
may rinse any remaining solution down the drain. Make sure your area is clean
before you return to your seat.
Post-Lab Questions:
1. In what ways is heat involved in chemical change? Support your answer with
examples from this experiment.
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2. In the last step of the experiment, where is the aluminum chloride? How could
you recover it?
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3. What is the color of solutions of copper compounds? _____________________
Name: _____________________________________ Date: __________________ Period: _____
4. Which substances involved in this experiment dissolved in water? Which
substance did not dissolve in water?
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Refer to the laboratory procedures to complete the following word equations.
5. Copper(II) nitrate + sodium hydroxide  ______________________________
6. Copper(II) hydroxide + heat  ______________________________________
7. Copper(II) oxide + hydrochloric acid  _______________________________
8. Copper(II) chloride + aluminum  ___________________________________
9. Hydrochloric acid + aluminum  ____________________________________
State whether the following substances are a compound or an element.
10. Copper(II) Nitrate:
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11. Sodium Hydroxide:
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12. Copper(II) Hydroxide:
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13. Sodium Nitrate:
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14. Copper(II) Oxide
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15. Water:
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16. Hydrochloric Acid:
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17. Copper(II) Chloride:
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18. Aluminum:
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19. Copper:
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20. Aluminum Chloride:
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21. Hydrogen:
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