Analía Bellizzi – Chemistry Classes

Ronald Reagan High School

AS Stoichiometry Cu+AgNO3 reaction

Copper-Silver Nitrate Reaction

Introduction

In this experiment, a solution of silver nitrate will react with copper wire.  Silver metal will be produced.  Careful measurements will enable you to determine the mole relationships between the reactants and products.

Materials:

  • Copper wire 15 to 25 cm length 16 or 18 gauge
  • Vial of silver nitrate  containing between 1.00 and 1.40 g
  • Triple beam balance (0.01g precision or better)
  • 250 mL beaker
  • Test tube (18x150mm)
  • Ring stand and test tube clamp
  • Stirring rod
  • Distilled water
  • Acetone

Procedure DAY 1

  1. Obtain the of copper wire and a vial of silver nitrate.
  2. Find the mass of each of these to the nearest 0.01 g.  Use the same balance for all your measurements in this experiment.  Record your measurements in the table below.
  3. Record the properties of copper wire and solid silver nitrate.
  4. Clamp a clean 18 x 150 mm test tube to a ring stand.
  5. Add about 20 mL of distilled water to the test tube.
  6. CAREFULLY add the silver nitrate from the vial to the test tube, stir gently to dissolve the crystals.
    CAUTION: silver nitrate, solid or solution, will stain your skin and clothing.  Avoid contact, and rinse immediately with water if contact occurs. 
  7. Be sure to rinse the stirring rod with a small amount of distilled water into the test tube when you are done stirring the solution.
  8. Coil the copper wire by wrapping it around a pencil.  Stretch the wire until it is about 2 cm longer than the test tube.  make a hook at the end so it can be hanged from the test tube.
  9. Place the coiled wire into the test tube with the silver nitrate solution so that is hanging from the test tube.
  10. Note the reaction that occurs; record your observations.
  11. Allow the reaction to continue for 30 minutes.
  12. MEANWHILE YOU WAIT for the reaction to take place:
    1. Find the mass of the empty silver nitrate vial to the nearest 0.01 g.
    2. Find the mass of the filter paper to the nearest 0.01 g.
    3. Work in the POST LAB QUESTIONS.
  13. After 30 min: Shake the silver crystals from the copper wire and remove the wire from the test tube.
  14. Dip the copper wire in acetone, then set it aside to dry. When it is dry, find its mass to the nearest 0.01g, then set it in the place directed by your instructor.
  15. Using the wash bottle, rinse the wire into the funnel containing the filter paper.
  16. Pour the contents of the test tube into funnel (you will need to use distilled water wash bottle to rinse it out).
  17. Rinse the silver from the test tube several times. be sure that the test tube does not contain any silver crystals and all of them are now in the paper filter.
  18. Allow the silver to settle, then rinse the paper filter containing the crystals 3 more times using only distilled water.
  19. Discard the filtrate and keep the residue.
  20. After the final rinse, the silver contained in the paper filter (residue) on a secure place to dry.

Procedure DAY 2

  1. When the silver is dry, find the mass of the beaker and silver to the nearest 0.01g.
  2. Then, place the beaker in the fume hood, and pour 5.0 mL of 6M HNO3 (nitric acid) into the beaker.  The nitric acid reacts with the silver producing the reddish-brown NO2 gas (quite noxious, do not smell it) and turning the silver back into silver nitrate, AgNO3.
  3. This will be used in the next experiment.

Data Table

  • Mass of vial and silver nitrate =                                             g
  • Mass of empty vial =                                                            g
  • Mass of silver nitrate =                                                         g
  • Mass of copper coil before reaction =                                     g
  • Mass of copper coil after reaction =                                       g
  • Mass of copper reacted =                                                     g
  • Mass of filter paper & silver =                                               g
  • Mass of filter paper =                                                          g
  • Mass of silver produced in reaction =                                    g

QUESTIONS

  1. What is the color of the silver nitrate solution?
  2. Predict the changes expected in the copper wire as the reaction proceeds.
  3. How would you expect the solution to change as the reaction proceeds?
  4. What precaution must you take in terms of handling the silver nitrate solid and solution?
  5. After the silver stops forming on the wire, why is the solution less likely to cause stains on the skin and clothes?

Since we need to dry the silver nitrate before making any calculations, please use the sample data below to show your calculations:

  • Mass of vial and silver nitrate = 9.05 g
  • Mass of empty vial = 7.89 g
  • Mass of silver nitrate = 1.16 g
  • Mass of copper coil before reaction = 1.42 g
  • Mass of copper coil after reaction = 1.23 g
  • Mass of copper reacted = 0.19 g
  • Mass of filter paper & silver = 1.58 g
  • Mass of filter paper = 0.84 g
  • Mass of silver produced in reaction = 0.74 g
  1. Determine the mass of copper that reacted during the experiment.
  2. Convert this to moles of Cu.
  3. Determine the mass of silver produced during the experiment.
  4. Convert this to moles of Ag.
  5. What is the blue color in the solution obtained?
  6. Determine the value of the ratio moles Ag / moles Cu.  Be sure to use the appropriate SF.
  7. Determine the mass and then the number of moles of AgNO3 used in the lab.
  8. Determine the value of the ratio moles Ag / moles AgNO3.  Be sure to use the appropriate SF.
  9. Write down the balanced equation for the reaction
  10. Write down the ionic equation for the reaction.