Expt 024 -- Activity Series

Several metals and solutions of their salts are mixed and examined in order to determine their relative activity.

Background

• When one metal is more active than another it will replace the less reactive metal from its compounds. Example:
  • Zn + Cu(NO₃)₂ --> Cu + Zn(NO₃)₂
• By contrast, the reverse reactions does not occur:
  • Cu + Zn(NO₃)₂ --> No visible reaction
• By making several observations of metal/salt reaction pairs and determining which combinations show evidence of reaction, it is possible to write an ordered series with the most reactive metals at the top and the least reactive at the bottom.

Safety

Several of the compounds are toxic. Wear goggles and apron. Do not ingest the chemicals. Wash hands before leaving the laboratory.

Procedure

1. Place 10 drops of zinc nitrate solution in the first well of a 12-well strip, 10 drops of ferrous ammonium sulfate solution in the second well, and 10 drops of silver nitrate solution in the third well. Cut 3 small pieces of copper metal and add one piece to each well. Allow the strip to stand at least 5 minutes. Observe and record any reactions. (Continue with the remaining procedures while these mixtures stand.)

   !!!Click here to See Picture.

2. Skip one well and place 10 drops of copper nitrate solution in well 5, 10 drops of ferrous ammonium sulfate solution in well 6, and 10 drops of magnesium nitrate solution in well 7. Add a small piece of shiny zinc metal to each well. Observe and record the results. Note any color changes on the surface of the metal as well as color changes of the solutions.

   !!!Click here to See Picture.

3. Wash hands.
4. Create a list of the metals used placing the most reactive metal on top and the rest in decreasing order of reactivity with the least reactive placed at the bottom.

Questions

1. Identify the most reactive metal and the least reactive metal on the list.
2. Sometimes magnesium metal is used to protect steel-hulled ocean going vessels from corrosion. Suggest a way in which this protection might work.
3. Suppose shiny pieces of manganese metal are available. Suggest experiments that will allow Mn to be inserted into this list.

Handout Makeup

Name ___________________________ Class ________

Teacher__________________________

SmallScale 024 Activity Series

Watch the movies and record your observations.

1. Create a list of the metals used placing the most reactive metal on top and the rest in decreasing order of reactivity with the least reactive placed at the bottom.
2. Use the pictures to answer the questions.

Curriculum-

Use this experiment early in a discussion of activity series, oxidation, reduction, and redox. In applied chemistry classes, this experiment relates to metal corrosion.

Safety-

Several of the compounds are toxic. Wear goggles and apron. Do not ingest the chemicals. Wash hands before leaving the laboratory.

Time-

Teacher Preparation: 20 minutes

Class Time: 30 minutes

Materials-

• The following solutions stored in pipet storage devices:
  • 1.5 mL of 0.1 M Fe(NH₄)₂(SO₄)₂•6H₂O (Dissolve 3.921 g ferrous ammonium sulfate hexahydrate ((NH₄)₂Fe(SO₄)₂•6H₂O) in enough water to make 100 mL solution.)
  • 1 mL of each of the following solutions is recommended.
  • 0.1 M Zn(NO₃)₂ (Dissolve 2.98 g zinc nitrate (Zn(NO₃)₂•6H₂O) in enough water to make 100 mL solution.)
  • 0.1 M Cu(NO₃)₂ (Dissolve 2.416 g copper(II) nitrate trihydrate (Cu(NO₃)₂•3H₂O) in enough water to make 100 mL solution.)
  • 0.1 M Mg(NO₃)₂ (Dissolve 2.56 g magnesium nitrate hexahydrate (Mg(NO₃)₂•6H₂O) in enough water to make 100 mL solution.)
  • 0.1 M AgNO₃ (Dissolve 1.70 g silver nitrate (AgNO₃) in enough water to make 100 mL solution.)
• The following metals stored in microcentrifuge tubes:
  • zinc metal
  • copper metal
• 12-well strip
• cotton swabs
• 5 storage pipets with soln.
• 2 microcentrifuge tubes with solids
• 1 audio-tape case for storage.
• Store reagents in kits

Disposal-

The solids used in this experiment may be disposed of with ordinary solid trash. The solutions used should be gathered in a disposal jar. Treatment with 1 M HCl precipitates AgCl. Filter. Save the solid for use in a silver recovery process. Neutralize the filtrate with Na₂CO₃ and discard at the sink with large amounts of water.

Data Table-

Cu + Zn²⁺ --> no reaction

Cu + Fe²⁺ --> no reaction

Cu + Ag⁺ --> reaction

Zn + Cu²⁺ --> reaction

Zn + Fe²⁺ --> reaction

Zn + Mg²⁺ --> no reaction

Data Analysis-

Mg(Zn does not react with Mg²⁺)

Zn (Zn reacts with Fe²⁺ but not Mg²⁺)

Fe (Fe²⁺ reacts with Zn but not Cu)

Cu (Cu reacts with Ag⁺ but not Fe²⁺)

Ag (Ag⁺ reacts with Cu)

Answers-

Q1. Identify the most reactive metal and the least reactive metal on the list.

A1. Mg is the most reactive metal; silver is the least reactive on this list.

Q2. Sometimes magnesium metal is used to protect steel-hulled ocean going vessels from corrosion. Suggest a way in which this protection might work.

A2. The magnesium is oxidized in preference to the iron when a block of magnesium is attached to the hull. This block can be replaced as it is consumed by oxidation.

Q3. Suppose shiny pieces of manganese metal are available. Suggest experiments that will allow Mn to be inserted into this list.

A3. Add shiny pieces of manganese metal to each of the available solutions, and note evidence for reaction. (Manganese is above zinc and below magnesium according to literature tables.)

Key Words 1-

activity series, oxidation, reduction, redox, corrosion,

Elements-

Ag Cu Mg Zn Fe