Which one Reacts?
Activity Series
Objective: An activity series of six substances can be developed from performing and observing a series of single replacement reactions.
Review of Scientific Principles:
When two different metals are in contact with each other or simply wetted with a solution containing sufficient ions to carry an appreciable electric current, an electrochemical cell is formed. The more active of the two metals will be consumed by the reaction.
Applications:
Understanding the chemistry of metals leads to the development of methods to reduce and prevent corrosion. Two metals may be used together; the more active one corrodes, sacrificing itself to save the other.
Time: 30 minutes
Materials and Supplies:
6 pieces of zinc, 1 cm by 1/2 cm
6 pieces of copper, 1 cm by 1/2 cm
6 pieces of magnesium, 1 cm by 1/2 cm
6 pieces of lead, 1 cm by 1/2 cm
optional - 6 pieces of iron
0.1 M AgNO3 about 1 ml - 1.7g/100 ml
0.1 M CuSO4 about 1 ml - 2.5 g/100 ml
0.1 M MgSO4 about 1 ml - 1.2 g/100 ml
0.1 M ZnSO4 about 1 ml - 2.9 g/100 ml
0.1 M Pb(NO3)2 about 1 ml - 3.3 g/100 ml
3 M HCl
24 hole cell well plate or 13 x 100 mm test tubes, rack, and test tube brush beral pipettes filled with the six solutions above forceps
General Safety Guidelines:
Procedure:
Questions:
1. Draw a chart similar to the cell well plate and record your observations in that chart.
2. Write single replacement equations for those reactions that occurred.
3. Draw and fill in a chart showing which substance in each of the above reactions is more active and which is less active. The six substances for comparison are magnesium, silver, hydrogen, copper, lead, and zinc.
4. Which of the six substances always ended up less active? Which always ended up more active?
5. Use the chart you created in question 3 to rank the six substances from most active to least active.
Teacher Notes:
Questions:
1. Student chart. The students should note reactions between any more active metal with a less active cation.
2. A sample reaction would be one between magnesium and copper (II) sulfate.
Mg (s) + CuSO4 (aq) --> MgSO4 (aq) + Cu (s)
3-5. The order of activity, from most to least active, is: Mg Zn Fe Pb H Cu Ag