Chem/FER
LAB: Types of Chemical Reactions
Name
Date
Block
This lab will demonstrate the four major types of chemical reactions:
combination (or synthesis), A + B  AB
decomposition,
AB  A + B
single displacement,
A + BX  AX + B
double displacement,
AX + BY  AY + BX
PURPOSE
1. To observe examples of each of the four major types of chemical reactions;
2. To identify the reactants and products of those reactions;
3. To classify each reaction observed;
4. To write balanced chemical equations for each reaction observed.
EQUIPMENT/MATERIALS (per 4 students)
Bunsen burner
small pieces of zinc, Zn(s)
crucible tongs
two 5-cm pieces of clean copper wire, Cu(s)
scoopula
two pieces of Mg(s) ribbon:
evaporating dish
one 3-cm piece, and one 0.5-cm piece
2 small test tubes
test tube rack
test tube holder
large Beral pipettes containing the following aqueous
fine gauge steel wool
solutions:
microwell plate
0.1 M barium chloride, BaCl2(aq)
matches
6.0 M hydrochloric acid, HCl(aq)
access to an electronic balance
0.1 M copper(II) sulfate, CuSO4(aq)
Q-tips™
0.1 M lead(II) nitrate, Pb(NO3)2(aq)
safety goggles/apron
0.1 M sodium sulfate, Na2SO4(aq)
1 test tube brush
0.1 M sulfuric acid, H2SO4(aq)
2 50-mL beakers
(note: the “0.1 M” is the concentration of the solution)
· 5 H2O (s)
small sample of cobalt(II) chloride hexahydrate (s), CoCl2 · 6 H2O (s)
small sample of copper(II) sulfate pentahydrate (s), CuSO4
PROCEDURE
This lab is to be completed in two (2) class periods. Each student table has a tray containing the
materials and equipment for all parts of the lab. One pair of students should do Parts I and II during
one class while the other pair of students does Parts III and IV. During the next class, the pairs of
students should complete the lab: the pair that did Parts I and II during the first class should do Parts III
and IV during the second class; the pair that did Parts III and IV during the first class should do Parts I
and II during the second class. DO NOT COPY THE OBSERVATIONS/ANSWERS FROM EACH
OTHER! Make your OWN observations.
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PART I: COMBINATION REACTIONS
1. Use a piece of fine steel wool to clean a piece of copper wire until the wire is shiny along its entire
length. Examine the cleaned wire and record its appearance in Table 1.
2. Light the Bunsen burner and adjust the flame to have a small bright cone. Using crucible
tongs, hold the copper wire in the hottest part of the flame until you observe a color change.
Examine the copper wire and record its appearance after having been heated in Table 1.
3. Place the evaporating dish near the Bunsen burner. Examine the 3-cm piece of magnesium
ribbon. Record its appearance in Table 1.
Using crucible tongs, hold the 3-cm piece of magnesium in the hottest part of the burner flame until
the magnesium begins to “burn.” Hold the “burning” magnesium over the evaporating dish. DO
NOT LOOK DIRECTLY AT THE MAGNESIUM WHILE IT IS “BURNING.”
When the magnesium stops “burning,” put whatever is left of it in the evaporating dish.
Turn off the burner at the gas jet. Examine this substance carefully and record your observations
in Table 1.
Disposal of materials: Return the copper wire to the plastic cup. Rinse the evaporating dish and
contents with water, then dry the evaporating dish.
PART II: DECOMPOSITION REACTIONS
1. Using a scoopula, add a small amount of solid copper(II) sulfate pentahydrate to a small
test tube. Observe the appearance of the dry solid and record your observations in Table 2.
2. Determine the mass of the test tube and dry solid. Record the mass in Table 2.
3. Hold the test tube with the test tube holder NEARLY horizontal and gently tap the test
tube to spread the dry solid along half of the length of the test tube.
4. Light the Bunsen burner as before but adjust the flame so that there is NO blue cone. You need a
cooler flame for this part of the lab.
5. Carefully and slowly move the test tube (still held nearly horizontally) back and forth through the
flame so that the entire sample is heated thoroughly. Heat the sample for about one (1) minute. If
any moisture forms at the mouth of the test tube, hold that area in the flame for a few seconds to
evaporate the droplets; then continue heating the solid. If the solid begins to darken, you have
heated it too much. Turn off the burner at the gas jet. Record observations AFTER heating in
Table 2.
6. Place the test tube and its contents in a small beaker and place a second small beaker upside down
over the test tube (this is to keep out as much moisture from the air as possible). Let the test tube
and contents cool for about 2-3 minutes. Then carefully remove the test tube and determine the
mass of the test tube and its contents. Record the mass of the test tube and its contents in Table 2.
Place the test tube and its contents in the test tube rack.
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7. Repeat Steps 1-6 using cobalt(II) chloride hexahydrate.
Disposal of materials: Empty the cool dry solids into the waste container on the demo table.
Clean out the test tube with water and the test tube brush.
PART III: SINGLE DISPLACEMENT REACTIONS
1. Place about 20 drops of 0.1 M copper(II) sulfate solution in a clean evaporating dish. Add the
0.5-cm piece of magnesium ribbon. Observe immediately and again after 5 minutes. Record
all observations in Table 3. Empty contents of dish into WASTE CONTAINER on demo
desk. Rinse the evaporating dish and dry thoroughly.
2. Place about 20 drops of 6.0 M hydrochloric acid(aq) in a clean dry evaporating dish. Add
one (1) small piece of zinc metal. Observe immediately and again after 5 minutes. Record all
observations in Table 3. Empty contents of evaporating dish into sink and then rinse dish
well and dry thoroughly.
PART IV: DOUBLE DISPLACEMENT REACTIONS
1. Record observations of the solutions of BaCl2(aq) and Na2SO4(aq) before combining them. Use
Table 4.
Add about 2 drops 0.1 M barium chloride(aq) to a clean dry microwell. Add about 2 drops 0.1 M
sodium sulfate(aq). Observe and record observations in Table 4. Allow a few minutes to let the
reaction go to completion. Empty contents of well into sink with lots of water. Rinse microwell
plate; to empty water from microwell plate, hold upside down over sink and snap wrist down
sharply. Use Q-tip™ to dry microwells.
2. Record observations of the solutions of Pb(NO3)2 (aq) and H2SO4(aq) before combining them. Use
Table 4.
Add about 2drops 0.1 M lead(II) nitrate (aq) to a clean dry microwell. Add about 2 drops
0.1 M sulfuric acid(aq). Observe and record observations in Table 4. Allow a few minutes to let
the reaction go to completion. Empty contents of dish into sink with lots of water. Rinse microwell
plate; to empty water from microwell plate, hold upside down over sink and snap wrist down
sharply. Use Q-tip™ to dry microwells.
3
DATA TABLES
TABLE 1. Synthesis Reactions (aka Combination Reactions)
Appearance of Metal BEFORE
Appearance of Metal AFTER
METAL USED
Heating in Air
Heating in Air
copper wire
magnesium
ribbon
TABLE 2. Decomposition Reactions
Mass in
grams of
test tube
and
contents
BEFORE Appearance of solid
Substance Used
Heating
BEFORE Heating
CuSO4 · 5 H2O (s)
CoCl2 · 6 H2O (s)
4
Mass in
grams of
test tube
and
contents
AFTER
Heating
Appearance of solid
AFTER Heating
TABLE 3. Single Replacement Reactions
REACTANTS
Observations Taken
Immediately After Combining
Reactants
Observations Taken After at
least Five (5) Minutes of
Reaction
Mg(s) + CuSO4(aq)
Zn(s) + HCl(aq)
TABLE 4. Double Replacement Reactions
REACTANTS
Observations BEFORE
Reaction
BaCl2(aq) + Na2SO4(aq)
Pb(NO3)2(aq) + H2SO4(aq)
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Observations AFTER
Reaction
IMPLICATIONS AND APPLICATIONS
1. Classify the following chemical reactions as single replacement (SR), double replacement
(DR), synthesis (S), or decomposition (D):
________ a) NaCl(aq) + AgNO3(aq) →
AgCl(s) + NaNO3(aq)
________ b) 2 Mg(s) + O2(g) → 2 MgO(s)
________ c) 2 HgO(s) → 2 Hg(l) + O2(g)
________ d) 2 Al(s) + 3 CuSO4(aq) → Al2(SO4)3(aq) + 3 Cu(s)
2. a) In general, is it possible to classify a chemical reaction from only one observation?
____________ (yes or no)
b) Explain why or why not.
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3. What types of information do you need to classify a chemical reaction accurately?
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Data Analysis and Concepts
Part I. Synthesis Reactions
1. What general evidence do you have that a chemical change occurred in each of the reactions?
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2. What characteristics do the synthesis reactions have in common (if any)?
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3. Write a skeleton equation to represent each reaction. You have been given the correct word
equations.
a)
copper (s) + oxygen (g) 
b)
magnesium (s) + oxygen (g) 
copper(II) oxide (s)
magnesium oxide (s)
4.
This type of reaction is referred to as a synthesis or combination reaction. Explain briefly
why this is an appropriate name for this type of reaction.
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Part II. Decomposition Reactions
5.
What general evidence do you have that a chemical change occurred in each reaction?
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6.
What characteristics do the decomposition reactions have in common (if any)?
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7. Write a skeleton equation to represent each reaction. You have been given the correct word
equations.
a)
copper(II) sulfate pentahydrate (s)  copper(II) sulfate (s) + water (g)
b)
cobalt(II) chloride hexahydrate (s)  cobalt(II) chloride (s) + water (g)
8.
This type of reaction is referred to as a decomposition reaction. Explain briefly why this is
an appropriate name for this type of reaction.
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Part III. Single Replacement Reactions
9. What general evidence do you have that a chemical change occurred in each of the reactions?
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10. What characteristics do the single displacement reactions have in common (if any)?
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11. Write a skeleton equation to represent each reaction. You have been given the correct word
equations.
a)
magnesium (s) + copper(II) sulfate (aq)  magnesium sulfate (aq) + copper (s)
b)
zinc (s) + hydrochloric acid 
zinc chloride (aq) + hydrogen (g)
12.
This type of reaction is referred to as a single displacement reaction. Explain briefly why
this is an appropriate name for this type of reaction.
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Part IV. Double Displacement Reactions
13. What general evidence do you have that a chemical change occurred in each of the
reactions?
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14. What characteristics do the double displacement reactions have in common (if any)?
_____________________________________________________________________________
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15. Write a skeleton chemical equation to represent each reaction. You have been given the
correct word equations.
a)
barium chloride (aq) + sodium sulfate (aq)  barium sulfate (s) + sodium chloride (aq)
b) lead(II) nitrate (aq) + sulfuric acid  sodium nitrate (aq) + lead(II) sulfate (aq)
12.
This type of reaction is referred to as a double displacement reaction. Explain briefly why
this is an appropriate name for this type of reaction.
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