Chemical Reactions of Copper
Background:
In this laboratory experiment solid copper is carried through five different chemical reactions to recover
as much of the solid copper as possible.
1. Copper reacts with nitric acid to produce aqueous copper (II) nitrate, nitrogen dioxide gas and water.
2. Sodium hydroxide is added to the copper (II) hydroxide and sodium nitrate.
3. Since copper (II) hydroxide is very gelatinous and hard to work with, it is heated to change it into copper
(II) oxide and water.
4. The copper (II) oxide is reacted with sulfuric acid to produce aqueous copper (II) sulfate and water.
5. Finally, the copper (II) sulfate is reacted with solid zinc to produce solid copper and zinc sulfate.
The copper is recovered and its mass is compared to the beginning mass to determine percent yield.
Objective:
1. To take copper through various types of chemical reactions and calculate the percent yield of the
recovered product.
2. To write chemical equations from written descriptions.
Procedure:
Day One:
1. Weigh to the nearest 0.0001 g approximately 0.500 g of copper. Place in a 400 ml or 250 ml beaker
cover and store in drawer.
2. Weigh out 2.0 g of zinc on weighing paper and store in drawer.
Day Two:
1. Measure out 100 ml of distilled water, leave in graduate cylinder to take to the fume hood.
2. Prepare about 250 ml of water to boil on hot plate.
3. (Step 3 will be done by your teacher under the fume hood.) Add 5 ml of concentrated nitric acid under
the fume hood. It is extremely important that a fume hood be used. The NO2 gas produce is deadly! If
all reaction has ceased and some copper still remains, add a small portion of nitric acid until all the
copper is dissolved. Add your pre-measured out 100 ml of distilled water to beaker. Record your
observations. Write an equation for this reaction
4. After all the copper is dissolved and the reaction has ceased, add 30.0 ml of 3.0 M NaOH. If solution
stays blue or precipitate dissolves upon stirring, add small amounts of NaOH. Record observations.
Write an equation for this reaction.
5. Gently heat solution while stirring, just to the boiling point. Record observations. Write an equation for
this reaction. Allow the black CuO to settle for several minutes. Carefully decant the supernatant (top)
liquid.
6. Add about 200 ml of very hot distilled water (prepared on step 2). Stir, and allow to settle for several
minutes. Decant supernatant liquid once again. This decanting and washing removes sodium nitrate
from solution.
7. Add 15 ml of 6.0 M H2SO4. Stir. Record observations. Write an equation of for the reaction.
8. Under the fume hood, add 2.0 g of zinc (prepared day 1 step 2) metal slowly- SLOWLY to reduce
copper ions to metallic copper. Stir. If the solution is still blue after the reaction stops producing gas,
add small amounts of zinc and allow to react until no further gas production is observed.
9. Decant supernatant liquid and discard. Record observation. Write an equation for the reaction.
10. In order to recover the solid copper, the remaining zinc must be removed. Add 20 ml of 6.0 M HCl and
allow to react. Once the bubbles have slowed, heat gently (DO NOT boil) until gas evolution stops.
11. Weigh a porcelain evaporating dish to the nearest 0.0001 g. Add 50 ml of distilled water to the beaker
containing the copper, stir. Decant supernatant with small amounts of distilled water to aid in the
transfer from the beaker to the porcelain evaporating dish.
12. Once transferred, Add 10 ml of distilled water to solid and swirl. Decant supernatant. Repeat this
washing two more times.
13. Wash the solid with 5 ml of methanol. (Keep away from flames.) Decant supernatant liquid and discard
in organic waste container.
14. Wash the solid with 5 ml of acetone, decant supernatant liquid and discard in labeled organic waste
container.
15. Evaporate the remaining acetone by placing the evaporating dish on a hot plate. Cover the dish with a
watch glass. Heat gently. Stir the solid occasionally while drying.
16. Cool the evaporating dish and weigh.
17. Dispose of copper solid as directed by instructor.
18. Clean up area.
Data:
Observations & Equations
1.
2.
3.
4.
5.
Measurements & Numbers
1. Mass of copper in the beginning
_________________
2. Mass of evaporating dish and copper
_________________
3. Mass of evaporating dish
_________________
4. Mass of copper in the end
_________________
Calculations (show balanced equations as part of calculations):
Pre-lab questions:
1. What are the different types of reactions?
2. Give the general equation for each of the 5 types of reactions:
a. ___________________________________________________________________
b. ___________________________________________________________________
c. ___________________________________________________________________
d. ___________________________________________________________________
e. ___________________________________________________________________
3. Define the below (give location in the room, describe lab procedure as they apply:
a. Supernatant –
b. Fume hood –
c. Precipitate –
d. Decant –
e. Wash –
4. What are some precautionary measures you should take in this lab?
5. What are some preparatory things you must do for this lab “day two”?
Post lab questions:
1. What kind of reaction did you see take place during this lab?
2. How do you utilize the solubility rules? What kind of information can we get derive from the list? How
is this helpful in lab results?
3. What is the purpose of washing with methanol and acetone?
4. Calcium carbonate, which is found in seashells, is decomposed by heating. CaCo3 (s)  CaO (s) + CO2
What is the theoretical yield of CaO if 24.8 g CaCO3 is heat? What is the percent yield if 13.1 g of CaO
is actually produced?