Name: ______Date: ______Period: ______

Reactivity of Metals

Adapted from Experiment 15: Reactivity of Metals Prentice Hall Laboratory Manual

Background:

The chemical reactivity of a metal determines how the metal is used. For example, gold, which is commonly used in jewelry, is highly resistant to chemical reactions. Sodium, however, is not used in jewelry because it is so reactive it will explode if it contacts water. The chemistry of the metals is based on their ability to lose electrons. Differences in chemical reactivity among metals depend on the relative ease with which they give up electrons.

You can measure the relative reactivity of two metals by placing a small pure sample of one metal in a solution containing the ions of the other metal. If the small metal sample is more reactive than the metal whose ions are in solution, electrons will move from the solid metal sample into the solution. For example, a piece of iron placed in a solution containing copper(II) ions will corrode, while fine copper particles deposit on the iron. However, no reaction occurs when a strip of copper metal is placed in a solution of iron(II) ions.
In this experiment, you will test the reactivities of a variety of metals with different metal ions. You will then use the results of your tests to construct a scale of relative reactivities of the metals.

Objective: To measure the relative reactivities of selected metallic elements.

Materials:

Tweezers

Glass-marking pencil

Well plate

Thin metal strips, 0.25 mm thick, approximately 2.00 x 0.50 cm:

2 strips of copper, Cu

3 strips of zinc, Zn

3 strips of magnesium, Mg

Solutions, 5% w/v, in dropper bottles:

Lead(II) nitrate, Pb(NO3)2

Silver nitrate, AgNO3

Copper(II) sulfate, CuSO4

Magnesium chloride, MgCl2

Zinc chloride, ZnCl2

Sodium chloride, NaCl

Potassium chloride, KCl

Safety Precautions: Wear your safety goggles and lab apron at all times. Solutions of lead and copper ions are toxic. Silver nitrate is toxic and will leave dark brown stains on skin and clothing. Return or dispose of all materials according to the instructions of your teacher.

Procedure: As you perform this experiment, record your observations in Data Table 1.

**For your observations, focus on solid formation and color change. Some reactions take time, so you may have to wait a few minutes to observe a change.

  1. Polish metal strips of copper (2), zinc (3), and magnesium (3) with steel wool until they are shiny.
  2. Using a sheet of white paper, place the well plate over the paper and number each well with numbers 1-8.
  3. To well 1, add 5 drops of Pb(NO3)2 solution.
  4. To well 2, add 5 drops of AgNO3 solution.
  5. Using tweezers, add one strip of copper metal to each well. Make sure the metal is submerged in the solution. Record your observations.
  6. Add 5 drops of solution to each well as follows: well 3, CuSO4; well 4, Pb(NO3)2; well 5 MgCl2.
  7. Add a strip of zinc metal to each well. Record your observations.
  8. Add 5 drops of solution to each well, as follows: well 6, ZnCl2; well 7, NaCl; well 8, KCl.
  9. Add a strip of polished magnesium metal to each well. Record your observations.
  10. Go back and see if any reaction has occurred in any of the well plates with some time. Record observations, if any.
  11. Clean up:
  12. Cu(s), Zn(s), and Mg(s) school trash (use tweezers to get them out).
  13. All reactions containing Pb(NO3)2 put in the waste bottle labeled Pb.
  14. All reactions containing AgNO3 put in the waste bottle labeled Ag.
  15. All reaction solutions except those containing Pb(NO3)2 or AgNO3 drain disposal.

Data Table 1: Observations of Metal Activity

Tube / Compound / Charge on Metal Ion / Metal / Observations
1 / Pb(NO3)2 / Pb2+ / Cu
2
3
4
5
6
7
8

Write balanced equations for the reactions in the lab. If a reaction did not occur, then the products would be “no reaction.” (Example: Na + MnCl2  No reaction)

Lab Analysis:

For 1-5 create an activity series for the metals tested in the lab by listing the metals in order of increasing activity. #1 should be the metal at the top of the activity series, #5 should be the metal at the bottom of the activity series.Options: Copper, Lead, Magnesium, Silver, Zinc

  1. Most reactive: ______
  2. Second most reactive: ______
  3. Third most reactive: ______
  4. Second least reactive: ______
  5. Least reactive: ______
  1. Using your data from the lab, would a reaction take place if zinc were placed in a solution of KCl?
  2. yes
  3. no
  1. A very reactive metal does not give up electrons easily.
  2. True
  3. False
  1. To which of the five general classifications of chemical reactions do the reactions in this lab belong?
  2. Combination
  3. Decomposition
  4. Single Replacement
  5. Double Replacement
  6. Combustion
  1. Based upon your results, why do you think jewelry is made of silver?