Single Replacement Reactions
Name:_______________
Period:____
PURPOSE: To observe and practice writing down molecular, complete ionic, and net
ionic equations for single replacement reactions.
THEORY: Most reactions in chemistry can be classified as one of two kinds: double
replacement (metathesis) reactions or single replacement reactions. In a double
replacement reaction, typically two aqueous solutions containing ionized or dissociated
species are mixed. Consequently ions in the solutions are brought into contact with one
another, with the possibility of creating a new compound that is either water (an acid base
reaction), a gas, or an insoluble salt.
Single replacement reactions typically occur when a solid metal is brought into
contact with an aqueous solution of another metallic salt. Depending on the activity, or
the relative ease with which the metal gives up its electrons, it can transfer electrons to
the cation of the metal in solution, resulting in the formation of a new metallic solid, and
the consequent dissolution of the original metal. Single replacement reactions can also
occur with the hydrogen ion, H+(aq) that can be donated from an acid such as HCl, or
even water if the metal has a high enough activity. Finally, the halogens can also be
involved in a series of single replacement reactions, with the relative activity being easily
deduced from the position of the halogens on the periodic table.
Before one can understand why chemical reactions occur, one must gain experience
predicting, observing, and recording the results of many different reactions. Typically
there are three kinds of equations that can be written down for a chemical reaction:
1) The molecular equation, in which all species are written together as formula units or
molecules, but the dissociation or ionization of compounds is not explicitly noted.
2) The complete ionic equation, which directly illustrates which species are ionized or
dissociated in solution.
3) The net ionic equation, which allows one to quickly determine what occurred in the
reaction, as it is created by deleting all spectator ions from the complete ionic
equation.
Today you will observe many chemical reactions and practice writing down these
equations for each one.
MATERIALS:
1) M solutions of the following:
Barium chloride
Potassium iodide
Copper(II) sulfate
Zinc nitrate
Magnesium nitrate
Sodium bromide
Silver nitrate
Sodium phosphate
1.0 M solutions of the following
Sodium carbonate
Hydrochloric acid
Lead(II) nitrate
Copper(II) nitrate
Potassium chloride
Solid samples of:
Copper
Magnesium
Zinc
Silver
Sodium
24 well plate (see figure below)
Plastic Beral Pipets
1% Phenolphthalein solution
Schematic Diagram of 24-well Plate (shown with where each metal is placed)
1
A
2
Copper
3
4
5
6
Copper
Copper
Copper
copper
Mg
Mg
Mg
Mg
Zn
Zn
B
Mg
C
Zn
Zn
Zn
D
Ag
Ag
Ag
Ag
Ag
PRELAB: All parts must be completed before you can begin the lab.
Copy the following tables exactly into your lab book. Use a minimum of a full page
for Table I
Data Table I – Single Replacement Reactions:
Well
A2
A3
A4
A5
A6
Reactants
Solid copper and
Magnesium nitrate
Solid copper and
Sodium nitrate
Solid copper and
Zinc nitrate
Solid copper and
Silver nitrate
Solid copper and
Hydrochloric acid
Observations
B1
B3
B4
B5
B6
C1
C2
C3
C5
C6
D1
D2
D3
D4
D6
Solid magnesium and
Copper(II) nitrate
Solid magnesium and
Sodium nitrate
Solid magnesium and
Zinc nitrate
Solid magnesium and
Silver nitrate
Solid magnesium and
Hydrochloric acid
Solid zinc and
Copper(II) nitrate
Solid zinc and
Magnesium nitrate
Solid zinc and
Sodium nitrate
Solid zinc and
silver nitrate
Solid zinc and
hydrochloric acid
Note: The D wells will be
Solid silver and
Copper(II) nitrate
Solid silver and
Magnesium nitrate
Solid silver and
Sodium nitrate
Solid silver and
Zinc nitrate
Solid silver and
hydrochloric acid
Done by the instructor
Data Table II – The Reaction of sodium with water
Experiment
One
Reactants
Solid sodium added to
water
Two
Solid sodium added to
water with
phenolphthalein
Observation
CALCULATIONS:
Single Replacement Reactions and the reactions of sodium.
For each reaction that occurred, write down the molecular, complete ionic and net ionic
equations for the reaction. Clearly show in your calculation which reaction well you are
discussing. For example, for well B1 you should write:
Reaction for well B1:
ME : Mg(s) + Cu(NO3)2(aq)  Mg(NO3)2(aq) + Cu(s)
CIE: Mg(s) + Cu2+(aq) + 2NO3-(aq)  Cu(s) + Mg2+(aq) + 2NO3-(aq)
NIE: Mg(s) + Cu2+(aq)  Mg2+(aq) + Cu(s)
Show this process for each reaction. If the same reaction occurred in more than one well,
you may write the reaction once, and then refer to it for subsequent wells. If no reaction
occurs, clearly state that. For example, if nothing happened in well C6, say
Reaction for well C6: No Reaction, or NR
Now look at your reactions. The solid metal that produced the greatest number of
reactions is the most active. From your data produce your own clearly labeled activity
series from the metals (Cu, Na, Mg, Zn, Ag) and the hydrogen ion. Compare your
ordering to that of the activity series in the text, explaining any differences.
Reactions of sodium:
Write down the ME, CIE, and NIE for this reaction.
DISCUSSION: Answer the following questions neatly and in complete sentences in your
lab book.
a) Explain the fundamental difference between single and double replacement reactions.
b) Recall we discussed the white coating that is formed on the sodium metal as it stands
in air. Write a balanced chemical equation for this reaction, and state what kind of
reaction this is.
c) Explain why the solution turned pink when phenolpthalein was added to the reaction
of sodium with water. What could be added to make the solution return to a clear
color?
d) Explain why one would never want to use water to put out a fire that involved an
alkali metal.
e) Why is sodium hydroxide the product of the reaction of sodium with water instead of
sodium oxide?
f) If one placed 25 g of sodium metal in water, how many grams of hydrogen gas would
be made?
Be sure to complete your lab with a meaningful conclusion!
Procedure: Single Replacement Reactions
A– Activity series of metals
1) Once again obtain a clean and dry well plate.
2) Place 20 drops of copper(II) nitrate into wells B1 and C1.
3) Place 20 drops of magnesium nitrate into wells A2, and C2
4) Place 20 drops of sodium nitrate into wells A3, B3, and C3.
5) Place 20 drops of zinc nitrate into wells A4 and B4
6) Place 20 drops of silver nitrate into wells A5, B5, C5,
7) Place 20 drops of hydrochloric acid into wells A6, B6, C6,
8) Insert one piece of copper metal into each filled well of the A row.
9) Insert one piece of magnesium metal into each filled well of the B row.
10) Insert one piece of zinc metal into each filled well of the C row.
11) The instructor will have a well set up showing the reaction of silver metal with each
solution. Make sure you look at this plate and record appropriate observations.
12) If needed, gently shake the well plate to submerge all of the metal. It is ok if a small
amount of the metal rests above the solution.
13) Record observations once all metal pieces have been inserted, and then again after 5
minutes. At this time the instructor will do the sodium demo. After this is completed,
make a final set of observations to see if anything has changed.
14) Dump the contents of all wells into the waste beaker provided. Use Q-tips to remove
any pieces of metal stuck in the wells. Clean the plate with soap solution, tap water,
and distilled water. Return to you desk for class discussion.
F – The reaction of sodium metal with water.
The instructor will demonstrate the reaction of sodium with water. Record observations
for both demonstrations.