Lab: Types of Chemical Reactions - OHS Chemistry
PRE-LAB DISCUSSION
There are many kinds of chemical reactions and many ways of classifying them. One popular and useful
method is to classify reactions into four major types. There are: (1) direct combination, or synthesis; (2)
decomposition, or analysis; (3) single replacement; and (4) exchange of ions, or double replacement. Not all
chemical reactions can be put into one of these categories. However, many can. See your chapter 8 notes for
details about them.
All of the types of reactions in this lab may be represented by balanced molecular equations. You will be
expected to balance the equations representing the observed equations.
2) PURPOSE
Observe some chemical reactions and identify reactants and products of those reactions. Classify the reactions
according to type and write balanced equations.
EQUIPMENT
MATERIALS
Burner
Crucible tongs
Scoopula
Test tubes 15x180-mm (7)
Test tube holder
Test tube rack
Evaporating dish
Wood splints
Fine sandpaper
Safety glasses
Zinc, mossy (Zn)
Copper wire, 5 cm. (Cu)
Magnesium ribbon (Mg)
Copper (II) carbonate (CuCO3)
6 M hydrochloric acid (HCI)
1 M Copper (II) sulfate (CuSO4)
0.1 M Zinc acetate (Zn(C2H3O2)2)
0.1 M sodium phosphate (Na3PO4)
1 M sodium sulfite (Na2SO3)
3) PROCEDURE:
Reaction 1
 Use fine sandpaper to clean a 5 cm. piece of copper wire until the wire is shiny. Examine the wire
and note its appearance.
 Using crucible tongs, hold the wire in the hottest part of the burner flame for 1-2 minutes.
Observe any changes that occur while the wire is being heated. Remove the wire from the flame
and note any changes in appearance caused by the heat.
Reaction 2
 Place an evaporating dish handy to the base of the burner. Examine a piece of magnesium ribbon.
(5 cm.) Using crucible tongs, hold the sample in the burner flame until the magnesium starts to
burn. DO NOT LOOK DIRECTLY AT THE FLAME UNLESS VIEWED THROUGH COBALT
BLUE GLASS. HOLD THE BURNING MAGNESIUM AWAY FROM YOU AND
DIRECTLY OVER THE EVAPORATING DISH. When the ribbon stops burning, put what is
left of it in the evaporating dish. Examine this product thoroughly.
Reaction 3
 Place a scoopula full of copper (II) carbonate (CuCO 3) in a clean, dry test tube (about 2 cm. in the
bottom of the tube). Note the appearance of the sample.
 Using a test tube holder, heat the CuCO3 strongly in the burner flame for about 3 minutes. Turn
off the burner and insert a flaming wooden splint in the test tube to test for the presence of carbon
dioxide gas. (CO2 will extinguish a fire) Note any change in the appearance of the material in the
test tube.
Reaction 4
 Add about 5 ml of 1 M copper (II) sulfate (CuSO4) solution to a clean, dry test tube. Place a small piece
of zinc metal in the solution. Note the appearance of the solution to the same test tube. Put the test tube
aside until the end of the period. At that time, observe what has happened, and note any changes in the
mixture
JLD; 4-14-11
Reaction 5
 Stand a clean, dry test tube in a test tube rack. Add about 5 mL of 6 M Hydrochloric acid (HCl) to
the tube. CAUTION: HANDLE ACIDS WITH CARE! THEY CAN CAUSE PAINFUL
BURNS! Carefully drop a small piece of zinc metal (Zn) into the acid in the test tube.
Immediately go on to Reaction 6. Observe and record what happens in Reaction 5.
Reaction 6
 Using a test tube holder, quickly invert a second test tube over the mouth of the test tube in which
the reaction is taking place.

Remove the inverted tube after about thirty seconds and quickly insert a burning wooden splint
into the mouth of the tube. (A "pop" indicates the presence of hydrogen gas) Note the appearance
of the substance in the second test tube. Record all observations.
Reaction 7.
 Add about 2 mL of 0.1 M zinc acetate (Zn (C 2H3O2)2) to a clean, dry test tube. Next, add about 2
mL of 0.1 M sodium phosphate (Na3PO4) solution to the same test tube. Observe what happens
and note any changes in the mixture.
Reaction 8
 Add about 5 mL of sodium sulfite (Na2SO3) solution to a clean, dry test tube. To this solution, add
about 1 mL of 6 M HCI. Heat it gently over the Bunsen burner, but do not boil it. Hold test tube
at a slight angle aimed away from any people. Observe the odor given off by wafting some of the
gas toward your nose. DO NOT DIRECTLY SNIFF THIS GAS!
4) HYPOTHESIS:
Using what you know about the various types of chemical reactions, write hypotheses using the IF-THENBECAUSE format to predict the type of the reaction in each step. This means that you will be creating eight separate
hypotheses. An example follows:
eg. If Na is added to Cl2 then it will be a synthesis reaction because Na is a metal and Cl is a nonmetal.
5) OBSERVATIONS AND DATA
Set up a data table in your lab book for observations of each of the above reactions. Allow an entire page for this
data table in order that you have plenty of space to make complete observations. Please remember to use a
straightedge to construct your table.
6) CALCULATIONS
Write and balance an equation for each of the above reactions. Write the word reaction below the balanced
molecular equation for that reaction. For example:
2Na(s) + Cl2 (g) → 2 NaCl(s)
Sodium metal plus chlorine gas yields solid sodium chloride
7) CONCLUSION:
Respond to your hypotheses using a table format to show whether each was supported or not and the data
evidence (note the table entries are examples only):
Hypothesis
1
2
3
4
Etc…
Supported?
yes
no
yes
yes
Data Evidence
Burned producing gas, combining with O2 from air
no precipitate formed, instead it bubbled indicating a gas
both reactants were solutions and a white AgI ppt formed
Pb is replaced by Al which appears as a dark sludge on the Al foil
10) QUESTIONS
1. In this experiment, what method was used to test for the presence of CO 2 gas?
2. What test was used to check for the presence of hydrogen gas? Write a balanced equation to represent this test,
3. Reaction 8 in the Calculations section above is actually represented by the following equation:
Na2SO3 (aq) + HCl(aq)  NaCl(aq) + H2O(l) + SO2(g)
In addition to double replacement, what other reaction type is represented by it? Explain.
JLD; 4-14-11