Name: __________________________
Chamberlain
Class: _______________
Lab : Types of Chemical Reactions
Purpose: A chemical reaction is a chemical change that takes place between two or more
elements. There are five basic types of reactions that we will study in this lab: synthesis,
decomposition, single replacement, double replacement, and combustion. This lab will introduce
you to these reactions and how they work.
Synthesis Reactions
Station 1
Caution: This portion of the lab is very dangerous. Do not look directly at the burning metal.
You must view it only through the blue or yellow glass. It will cause permanent blindness.
1. Place a precut strip of magnesium in the flame over a bunsen burner.
2. Record your observations below.
3. Write the balanced chemical equation for this reaction below. (Hint: When you burned the
magnesium, you were burning it in the air)
4. What evidence is there that a reaction took place?
5. On Mrs. C’s computer, Go to the website
http://jchemed.chem.wisc.edu/jcesoft/cca/CCA0/Movies/NACL1.html. Watch the
Quicktime video.
6. Record observations of the reaction in the space below:
7. Write the balanced equation for the reaction that takes place between sodium and chlorine.
8. Go to the website http://www.youtube.com/watch?v=N5h5ohd8298. Watch the video.
9. Record observations of the reaction in the space below:
10. Write the balanced equation for the reaction between iodine and aluminum.
Decomposition Reactions
Station 2
1. Place a few crystals of CuSO4 · 5H2O in a test tube.
2. Gently heat the crystals and record observations below:
3. After the test tube cools, add a few drops of water.
4. Record your observations below:
5. When you heated the compound initially and it decomposed, which product escaped the test
tube?
6. What evidence was there that a reaction took place?
7. Get a second test tube.
8. Place a small scoop of KIO3 into the test tube.
9. While gently heating the test tube, hold a glowing splint inside the mouth of the test tube.
10. Record your observations below:
11. What product do you think is given off?
Station 3
Electrolysis is the process in which electrical energy is used to bring about a chemical change.
Water can be separated by electrolysis.
1. Into a Petri dish, place 20 mL of distilled water.
2. Place two drops of universal indicator in the dish and stir with a clean glass stirring rod.
3. Clip the alligator clips onto the 9-volt battery.
4. Place the two tips of the electrolysis apparatus (pencils) in the water.
5. Gas bubbles will form at the end of the pencils.
At one of the pencil tips, the water will turn a deep purple. This means the water is turning
very basic due to the H2 being removed from the water molecules and leaving an OH- behind
in the water.
2H2O  O2 +
4H+
At the other pencil tip, the solution turns orange red due to the presence of H+ ions. This is
due to the removal of O2 from the water molecule. H+ makes the solution acidic.
2H2O  H2 +
2OH6. What evidence is there that a reaction is taking place?
7. Write the equation for the decomposition of water:
Single-Replacement Reactions
Station 4
Caution: Some of these reactions may be violent and produce a great deal of heat. Do not
hold test tubes with your hands. Place in wooden racks only.
1. Label a beaker #1 and the test tubes #2, 3, and 4.
2. Place the following solutions into each of four containers: #1-100 mL H2O, #2-15 drops
H2O, #3-15 drops 6M HCl, #4-15 drops 6M HCl
3. Add the following metals to each of the designated containers: #1 Ca, #2 Mg, #3 Zn, #4 Mg
4. Record your initial observations and observations after 5 minutes in the table below.
5. Discard the metals in the trash and the liquid products in the sink.
Container
#1 (Beaker)
Initial Observations
Final Observations
#2
#3
#4
4. Write a balanced chemical equation for all 4 reactions in the space below.
1.
2.
3.
4.
Double Replacement Reactions
Station 5
1. Place 10 drops of the following solutions into four corresponding test tubes:
#1 0.1 M MgSO4, #2 0.1 M Na2SO4, #3 1.0 M Al2(SO4)3, #4 CaCl2
2. Add 10 drops of the following solutions to each of the corresponding test tubes:
#1 0.5 M Na2CO3, #2 0.1 M BaCl2, #3 1 M KOH, #4 Na2CO3
3. Record initial observations and observations after 5 minutes in the table below.
4. Pour all solutions into the sink to dispose of them.
Test Tube
#1
Initial Observations
Final Observations
#2
#3
#4
4. Write balanced equations for each of the four reactions in the space below.
1.
2.
3.
4.
5. Choose one of the reactions that you wrote an equation for and write the complete ionic
equation and the net ionic equation in the space below:
Combustion Reactions
Station 6
1. Measure and record the length of a candle’s wick in centimeters: ______________________
2. Find the mass of the candle: ________________________
3. Light the candle and let it burn for 5 minutes. Answer the next 3 questions while the candle
burns.
4. Examine the flame closely as you watch the candle burn. Is it the wax or the wick that
burns?
5. If you said the wax, how does the wax burn without touching the flame? If you said the
wick, what is the function of the wax?
6. Scientists have often wondered if a candle would burn well in zero gravity. How would zero
gravity change the shape of the flame?
7. After letting the candle burn for five minutes again measure and record the length of a
candle’s wick in centimeters: ______________________
8. Find the mass of the candle: ________________________
9. How much length and mass did the candle lose?
10. Are these data consistent with the wax or the wick burning?
11. Based on your data and observations, explain below how you think a candle works.
12. The formula for candle wax can be approximated as C20H42. Write and balance an equation
for the combustion of candle wax. (Hint: Keep in mind what one of the reactants always is
in a combustion reaction and what the two products usually are. If you’re not sure, look in
your notes!)
13. Now that you know the formula for candle wax and you know the mass of it that burned,
how many moles of candle wax were burned in your experiment. (Hint: Remember last
unit?!?)
Station 7
1. Fill a 250 mL beaker mostly full with water and mix in a few drops of dishwashing liquid.
2. Attach a hose to a methane (CH4) gas source. Place the other end of the hose in the beaker
of soapy water. Slowly turn on the gas source and allow the gas to bubble through the water.
Bubbles should form. When you have a large number of bubbles, turn off the gas.
3. Take the hose out of the beaker.
4. Strike a match away from the beaker and once it is lit, carefully move it close to the beaker.
BE CAREFUL TO KEEP ANY FLAMMABLE MATERIALS AWAY FROM THE
BEAKER!!
5. Repeat this procedure 3 times.
Answer the following questions:
1.
What did you observe?
2.
Could regular dish soap bubbles be lit in the same manner? Why or Why not?
3.
Write the balanced chemical equation for the reaction that takes place:
4.
Why did the bubbles not combust until the match was present? (There is no fire in the
chemical equation!)