The Behavior of Solid Copper Immersed
in a Solution of Silver Nitrate
The reaction between metallic copper, Cu, and aqueous silver nitrate, AgNO3 (aq), is
described as an oxidation-reduction reaction. Silver ions, Ag+1 (aq), oxidize the copper
atoms in the metal to copper ions, reducing the Ag+1 ions to neutral silver atoms, Ag0, in
the process. To begin you will be issued a vial containing approximately 3.00 g to 4.00 g
of crystalline silver nitrate, AgNO3. After dissolving your pre-weighed sample of the
silver nitrate crystals in approximately 100 mL of distilled water, you will immerse a
piece of copper, Cu, to observe the reaction. By weighing the sample of metallic copper
before and both the copper and newly formed silver crystals at the close of the
experiment, you will be able to investigate any changes that occur quantitatively. During
the investigation, we want to determine the oxidation state of the copper ion produced.
Before coming to the lab, prepare a data table in your laboratory notebook so you can
record the data you will observe.
Caution: Silver nitrate, solid or in solution, reacts with skin and will stain it dark brown.
Be careful and avoid spillage on your skin and clothing. However, don’t be alarmed if
you discover dark spots on your hands - they will wear away in a few days. Clean hands
the day following this experiment indicate good lab technique!
Part I
1. Obtain a 30-cm piece of copper wire and form a coil as illustrated by your teacher (so
that it is ready for step #5 below). Weigh the coil to the nearest 0.01 g on the balance.
Include your uncertainty as you proceed, please.
2. Obtain a clean, dry 250-mL beaker and weigh it. Then add about 100 mL of distilled
water. (Note: Do not use tap water. The minerals may interfere with the experiment.)
3. Weigh the vial of silver nitrate crystals, AgNO3, and be sure to include its cap. Pour
the crystals carefully into the 250-mL beaker and dissolve them in the water. (You
may use a stirring rod, but make sure you clean off the stirring rod after mixing into
the beaker with a stream of distilled water from a wash bottle.)
4. Weigh the empty vial.
5. Place the coil into the beaker, positioning the hooked handle on the edge of the beaker
so that the coil is immersed in the silver nitrate solution. Observe any changes that
take place for several minutes.
6. Cover the beaker with a watch glass and place it down below in the cabinet. It must
sit overnight for the interaction to fully take place.
Part II
7. Very carefully open the cabinet and lift the beaker to the desk top. Observe what
has happened in the beaker. Record all your observations.
8. Very carefully shake the crystals off the coil and lift the
coil from the solution (but do not lose any crystals in the
process). Use a wash bottle to remove stubborn crystals
which tend to adhere to the coil.
9. Set aside the coil on a paper towel. You’ll weigh it again
tomorrow after it dries.
10. Decant the crystals from the solution into another clean
250-mL beaker. Use a Buchner funnel with vacuum
filtration to separate the copper solution from the silver.
Pre-weigh a piece of filter paper. Try your best to keep the silver crystals in the
original beaker.
11. We’ll save the decanted copper solution for further investigation.
12. Some flecks of copper may have left the coil in its cleansing and must be removed.
Pour 5 mL of dilute aqueous silver nitrate over the silver crystals in the beaker and
swirl gently until these copper flecks dissolve. Carefully decant again into the
Buchner funnel. Wash the crystals with 10 mL of distilled water and carefully
decant. Wash the residue at least three more times to remove all of the water-soluble
mpurities.
13. Once the final washings are accomplished, the filter paper and beaker containing the
crystals must be dried together in a drying oven over night. Hang your copper coil on
inside of the beaker for drying, too.
Part III
13. Obtain your dried sample and allow it to cool before weighing. Carefully scrape any
crystals that were captured by the filter paper into the beaker containing the crystals.
Weigh the 250-mL beaker, the filter paper, and its crystalline contents. Weigh the
copper coil, too. Use the same balance as you used previously and record the masses.
14. We can now study our data and compute a Ag:Cu mole ratio that highlights the
reaction between aqueous silver nitrate and metallic copper.
In addition, we will compile class data in order to the statistics associated with this
Ag:Cu mole ratio.
Post-Lab Analysis
Calculations & Questions
1. Determine the mass of copper, Cu, consumed in the reaction. Then convert the mass
of copper to moles.
2. Determine the mass of silver, Ag, produced in the reaction. Then convert the mass of
silver to moles.
3. Compute a mole ratio:
moles Ag
moles Cu
Remember to follow the significant figure rules.
4. Determine the class average mole ratio.
5. What is the significance of this mole ratio? Can we determine the oxidation state of
the aqueous copper ions produced?
6. What type of chemical reaction is observed when copper dissolves in aqueous silver
nitrate? Write the half-reactions and the overall reaction that explains the chemistry
going on.
6. How might this process for converting silver nitrate to elemental silver be useful to us
on a larger scale, say, industrially?
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