Name: _____________________________________________ Date: __________________ Period: _________
Behavior of solid copper in an aqueous solution of silver nitrate lab
Objectives
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In this experiment, you will determine the relationship
between the number of moles of copper and the number of
moles of silver involved in a chemical reaction.
You will find the mass of a sample of solid silver nitrate and
prepare a water solution of it.
You will also find the mass of a piece of copper wire, place it in
the solution, and observe its behavior.
By finding the mass of the copper wire at the end of the
experiment, you will be able to investigate quantitatively any
changes that occur.
Background Information
In keeping with chemical practice, we shall refer to the chemical substances by using appropriate symbols.
Copper is an element; it contains only one kind of atom. The symbol for copper is Cu. Silver nitrate (AgNO3) is
a compound and the formula identifies it by using the symbol Ag+ for the silver cation and the symbol NO3- for
the nitrate anion. The group of atoms, NO3- (consisting of one nitrogen atom and three oxygen atoms, plus an
electron) is often found in chemical compounds. It has the name: nitrate ion.
The following chemical equation represents the reaction that you will be experiencing in this lab. Solid copper
wire reacts with an aqueous solution of silver nitrate to yield solid silver crystals and a green/blue aqueous
solution of copper nitrate.
Cu(s) + 2AgNO3(aq)  2Ag(s) + Cu(NO3)2(aq)
Procedure – Day #1
1. Obtain a piece of heavy copper wire.
2. Straighten out the wire with your hands as well as possible.
3. Starting at one end of a pencil, coil the piece of heavy copper wire around the pencil to form a corkscrew
shape.
4. Find the mass of the spiral copper wire to the nearest 0.01 g and record this in the data table below.
5. Find the mass of a piece of weighing paper to the nearest 0.01 g and record this in the data table below.
Material
Copper wire
Weighing paper
Silver nitrate (AgNO3)
Mass (before)
6. With the weighing paper on the pan of the balance, its mass already recorded, zero the balance.
7. Then open the silver nitrate (AgNO3) container and tap out crystals until exactly 3.00 g have been added to
the weighing paper and record this in the data table above.
8. Put about 10mL of distilled water into a clean, dry 50mL beaker.
9. Add the solid silver nitrate (AgNO3) to the water and swirl gently until all the solid has dissolved (Caution:
silver nitrate, solid or solution, reacts with skin and turns it black. Be careful to avoid spillage on your skin
or clothing.).
10. Pour the silver nitrate solution into a test tube.
11. Rinse out the beaker with two 5mL portions of distilled water. Add the rinses to the solution in the test
tube.
12. Mix with a stirring rod.
13. Rinse off the stirring rod with a small quantity of distilled water. Add this rinse to the test tube.
14. Put one end of the copper wire into a one-hole no. 2 rubber stopper. Make sure a bit of the
copper wire bends over the top of the rubber stopper.
15. Place the copper wire assembly into the the test tube and loosely fit the rubber stopper into the
top of the test tube.
16. Make sure the water level is just below the rubber stopper. If the water isn’t, then remove the
stopper and add more distilled water until it is at a level right below the stopper.
17. For several minutes, observe any changes that take place.
Observations
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18. Place the test tube assembly in a rack designated for your class period.
19. The test tube assembly will stand for the next few days so that the reaction can go to completion.
Procedure – Day #2
1. Retrieve your test tube assembly and place in a test tube rack on your desk.
2. Make any observations that have taken place in the test tube.
Observations
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3. Obtain a ring stand, a ring clamp, a funnel, and a 250mL beaker. Set up your
equipment like the picture to the right.
4. Determine the mass of a piece of filter paper to the nearest 0.01g and record this in the data table below.
Material
Filter paper
Mass (after)
5. Fold the filter paper into 4 quarters creating a cone.
6. Fit the filter paper cone into the funnel and moisten it with some distilled water so that it stays in place.
7. Pick up your test tube assembly and loosen the rubber stopper. Holding the rubber stopper, shake the
silver crystals off the wire, into the test tube.
8. Remove the rubber stopper and copper wire from the test tube. Hold the rubber stopper and the wire
over your filter paper and funnel setup. Use your wash bottle to rinse any silver crystals that are stuck to
the copper wire onto the filter paper. (Caution: Do not poke holes in your filter paper with the wire.) If
you have silver crystals that cannot be removed, use a glass stirring rod, to loosen them, and then rinse
with distilled water onto the filter paper.
9. Remove the copper wire from the rubber stopper.
10. Set the copper wire on a paper towel to dry. You may have to dry the copper wire with a paper towel to
remove any remaining water.
11. Determine the mass of the remaining copper wire to the nearest 0.01g and record this in the data table
below.
Material
Copper wire
Mass (after)
Copper wire used in the reaction
12. Calculate how much copper wire was actually used in the reaction. Record this in the data table above.
13. Pick up the test tube containing silver crystals and a green/blue aqueous solution and pour the contents
onto the filter paper. Collect the blue solution in the 250mL beaker located underneath the funnel.
14. Use your distilled water bottle to rinse out any particles of silver that may have been left behind in the test
tube. Wash the test tube thoroughly with distilled water. Your goal is to obtain as much silver as possible.
You do not want to leave any behind in the test tube.
15. After the filtration process is complete, observe your green/blue aqueous solution. Is there any silver still
in the solution? If so, you will have to repeat the filtration process making sure to obtain all silver onto the
filter paper.
16. Obtain a clean, dry 150mL beaker.
17. Determine the mass of this 150mL beaker to the nearest 0.01g and record this in the data table below.
Material
Beaker
Mass
18. Remove the filter paper cone with the silver and place it into this clean, dry beaker.
19. Place your beaker with the filter paper cone and silver in the tray designated for your class period.
20. It should be dry when you return to the laboratory the next day.
Procedure - Day #3
1. Retrieve your beaker with the filter paper cone containing your dried silver.
2. Determine the mass of the beaker with the filter paper cone containing your dried silver to the nearest
0.01g and record this in the data table below.
Material
Beaker + filter paper + silver
Mass
3. Calculate how much silver you formed in this reaction and record this in the data table below.
Material
Silver
Mass
4. Return the silver to your teacher for reclaiming. She is going to melt it down and make herself earrings!!!
5. Write the initial mass of the silver nitrate, AgNO3 used to begin the reaction: ___________________ grams
a. What is the molar mass of , AgNO3? ____________________ grams/mole
6. Use the initial mass of the silver nitrate in question #5 as the given to calculate the number of moles of
silver nitrate, AgNO3, that reacted. (Hint – you’ll need to use the molar mass from #5a to complete the
conversion). Record this number in the data table below.
Moles of Silver nitrate
________________ moles AgNO3
7. Write the mass of the silver formed: ____________________ grams
a. What is the molar mass of silver? ____________________ grams/mole
8. Use the mass of the silver formed in question #7 as the given to calculate the number of moles of silver
that reacted. Record this number in the data table below.
Moles of Silver
________________ moles Ag
9. Write the mass of the copper wire used in the reaction: ____________________ grams
a. What is the molar mass of copper? ____________________ grams/mole
10. Use the mass of the copper wire used in questions #9 as the given to calculate the number of moles of
copper that reacted. Record this number in the data table below.
Moles of Copper
________________ moles Cu
11. Determine the mole ratio of moles Ag/moles Cu. Record your answer as a decimal in the data table below.
Mole Ratio
moles Ag/moles Cu
12. Determine the ratio of moles of Ag/moles of AgNO3. Record your answer as a decimal in the data table
below.
Mole Ratio
moles Ag/moles AgNO3
13. Collect the results obtained by 7 other groups in your class.
Group
Own (1)
2
3
4
5
6
7
8
Decimal Ratio of moles Ag/moles Cu
Results:
1. Find the class average for the mole ratio of moles Ag/moles Cu
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2. Find the overall average of all classes for the mole ratio of moles Ag/moles Cu
__________________
3. Find the actual mole ratio of moles Ag /moles Cu by looking at the balanced equation
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4. Find the % error for moles Ag/moles Cu using your mole ratio from #11 (experimental) and the actual mole
ratio that you just calculated.
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5. Find the actual mole ratio of moles Ag/moles AgNO3 by looking at the balanced equation
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6. Find the % error for moles Ag/moles AgNO3 using your mole ratio from #12 (experimental) and the actual
mole ratio that you just calculated.
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Conclusion:
1. What is Avogadro’s number?
__________________________ atoms = ______________________ mole
2. How many atoms of copper metal were involved in your experiment (use Avogadro’s number)?
3. How many atoms of silver metal were produced in your experiment (use Avogadro’s number)?
4. What causes the color in the solution after the reaction is completed?
5. What elements and/or compounds are remaining in the water solution after filtration?
6. All experiments have a % error. Discuss two errors that led you to have the % error that you calculated
above.