Relative Reactivity of a Group of Metals
Introduction:
Some metals react with dilute
aqueous solutions of hydrochloric acid and other metals do not. The reaction
may be very fast or very slow. The rate of the reaction, at constant
temperature and concentration, may be used as an estimate of the activity of a
metal. We say the metal is very active when hydrogen gas is released very
rapidly.
We can construct a table of
"activity" in which metals that react in acid solution are placed
above hydrogen, while metals that don’t react in acid are placed below hydrogen
in the series. The faster the metals react in acid solution, the further up the
table they are placed.
Metals can also be placed in a table depending on whether or not they take part in single displacement reactions. The general rules for order in the series are:
1. Metal M is more reactive than metal N when metal M reacts
with a solution containing a compound of metal N
2. Metal M is less reactive than metal N when metal M does
not react with a solution containing the compound of metal N
Objectives:
1.
To
observe the reaction or non-reaction of a series of metals and metal ion
solutions.
2. To construct an activity series for metals.
Materials:
Test tube rack, 9 test tubes, magnesium, zinc, copper, MgSO4
(aq), ZnSO4 (aq),
and CuSO4 (aq)
Procedure:
Part A
1. Obtain a sample of magnesium ribbon, solid zinc and a piece of copper. Examine each sample and record observations such as color, texture, and luster.
2. Obtain three test tubes and add 3 mL of 6M HCl.
3. Add the magnesium strip to the first test tube and record your observations. Include how the sample changed from its original form.
4. Add the solid zinc to the second test tube and record your observation. Include how the sample changed from its original form.
5. Add the piece of copper to the third test tube and record your observations. Include how the sample changed from its original form.
Part B
1. Add a strip of magnesium to three clean test tubes.
2. Add 3 mL of MgSO4 (aq) to the first test tube and record your initial observations and record observations after 10 minutes.
3. Add 3 mL of ZnSO4 (aq) to the first test tube and record your initial observations and record observations after 10 minutes.
4. Add 3 mL of CuSO4 (aq) to the first test tube and record your initial observations and record observations after 10 minutes.
5. Repeat steps 1-4 with zinc and with copper.
Data Table:
Constructed based on the procedure and allows enough space for appropriate answers.
Analysis:
1. Write balance chemical equations for the reactions of the three metals with HCl (aq) in Part A.
2. Write a balance chemical equation for each reaction that took place in Part B.
3. Arrange the metals in decreasing order of reactivity
4. Interpret chemical reactivity in terms of general single- replacement principles
Questions:
1. Silver does not react with hydrochloric acid. Will silver react with a solution of aluminum nitrate? If so, write the chemical equation for the reaction.
2. Will aluminum react with a solution of silver nitrate? IF so, write a chemical equation for the reaction.
3. Lead will react very slowly with hydrochloric acid. Aluminum will react with lead (II) sulfate solution. Will lead react with silver nitrate solution? IF so, write a chemical equation of lead silver nitrate solution.
4. On the basis of information in the previous three questions, arrange silver, aluminum, and lead in order of decreasing reactivity.
5. When magnesium is added to copper (II) sulfate solution, what specific observations would indicate that a reaction has occurred?
Conclusion:
In your conclusion,
make specific references to objective(s) and results. The conclusion should also include sources of
experimental error and suggestions for improvement that are thoughtful and well
written. Be concise!