Name
Lab Day
Activity of Metals and Ions
Introduction:
The chemical reactivity of elements varies widely. Some elements,
e.g., sodium, are so reactive that they are only found in compounds in
nature, never as the free metal. Other elements, e.g., helium, are so
stable as to be relatively inert. The reactivity of a metal atom is related to
its tendency to lose or gain electrons. It should be possible to arrange a
small group of metals into an activity series. A series of this kind would
indicate which uncombined metals would be capable of displacing other
metals from their aqueous compounds.
In this experiment, you will examine the relative tendencies for
certain metals to replace one another in compounds, and you will then
use your observations to arrange them in order of reactivity. The
reactions will all be single replacement (displacement) reactions where a
metal element is replacing a metal ion in an aqueous compound.
M0 + X+2 A–2 → M+2 A–2 +
metal
X0
metal
ion
If metal M is the more active metal it will replace metal X from the
compound XA. If metal X is more active than metal M, no reaction will
occur.
Experimental:
Place 12 clean test tubes in a rack. Label them. To each, add about
5 mL of the solutions listed below.
Obtain three pieces of each of the following metals: zinc,
magnesium, copper, and lead. Clean the metals with steel wool to expose
fresh metal surfaces. Add the metals to the test tubes with the solutions
as listed.
Tube 1: zinc metal + magnesium nitrate
Tube 2: magnesium metal + zinc nitrate
Tube 3: zinc metal + lead(II) nitrate
Tube 4: lead metal + zinc nitrate
Tube 5: magnesium metal + copper(II) sulfate
Tube 6: copper metal + magnesium nitrate
Tube 7: copper metal + zinc nitrate
Tube 8: zinc metal + copper(II) sulfate
Tube 9: copper metal + lead(II) nitrate
Tube 10: lead metal + copper(II) sulfate
Tube 11: lead metal + magnesium nitrate
Tube 12: magnesium metal + lead(II) nitrate
2
Look for evidence of a reaction (which will occur in some cases, but
not in others). Evidence may be the formation of new metal flakes, or a
change in appearance of the original metal or solution. Metals deposited
from a solution are often black or gray (in the case of copper, very
reddish brown) and do not look like commercially prepared metals.
Pour the solutions in the waste container on the cart. Rinse the
metals with water and throw them in the trash (not down the sink!).
Write your observations in the table provided below:
Compounds in solution
metal
↓
Zn
Mg
Cu
Pb
Zn(NO3)2 (aq)
Zn+2 (aq)
Mg(NO3)2 (aq)
Mg+2 (aq)
CuSO4 (aq)
Cu+2 (aq)
Pb(NO3)2 (aq)
Pb+2 (aq)
3
For Zinc:
1.
Which aqueous compounds reacted with zinc metal?
2.
Write a balanced equations for any reactions with zinc metal (write
the oxidation number of each metal atom or ion over its symbol).
3.
For those reactions that occurred, was zinc losing or gaining
electrons?
4.
Which metal is the most reactive: Zn, Cu, or Pb?
For Magnesium:
1.
Write balanced equations for the reactions that occurred with Mg
metal and identify the substances losing electrons and gaining
electrons in the reactions.
2.
Which metal is the most reactive: Zn, Mg, Cu, or Pb?
4
For Lead:
1.
Write balanced equations for the reactions that occurred with the
lead metal and identify substances losing and gaining electrons.
2.
Which metal is most active: Pb or Cu?
For Copper:
1.
Did Cu react with any of the aqueous compounds containing ions
of the other metals?
Summary:
1.
Arrange the four metals used in this experiment in order of ability
to displace metal ions from aqueous solutions (put most active on
top).
most reactive
activity of metals used in lab
2.
How does your order compare to that on the activity series of
metals found in your power-point slides?