Classifying Reactions
Lab
Classifying Reactions Lab
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Unit 5, Lesson 12
Classifying Reactions Lab
• Safety Reminder: Wear safety glasses and use ammonia
in a well-ventilated area.
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Objectives:
Identify different types of reactions
Predict the products of reactions
Balance chemical equations
Materials Needed for Whole Lab
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Small glass jars (2)
Steel wool
Water
Dish with sides
Hydrogen peroxide
Potato
Penny
Sandpaper or nail file
Small bowl
Penny dated after 1983
Vinegar
Epsom salts
Ammonia
Small cup
Measuring cup
Part I:
Reaction between Iron and Oxygen
Part I Materials:
• small glass jars
• dish with sides (a pie plate works well)
• Steel wool
• Water
Part I:
Reaction between Iron and Oxygen
Part I Procedures:
• Soak a small piece of steel wool in vinegar for one minute. Use tweezers to push the
steel wool around in the vinegar to remove bubbles.
• Lift the steel wool out of the vinegar with tweezers and shake it gently over a paper towel
to remove excess vinegar.
• Stretch the wool out.
• Gently push the steel wool into the bottom of a baby jar.
• Add water to a small bowl until the water is about three-quarters of an inch deep.
• Invert the baby food jar and place it in the bowl of water.
• No water should be inside the baby food jar at this point (you have trapped air in the
baby food jar).
• Leave for 20 minutes and then record observations.
Part I Questions and Conclusions
Reaction between iron and oxygen
1. Balance the equation, if necessary, for the reaction between iron
and oxygen.
Fe + O2  Fe2O3
Hint: There must be the same number of Fe’s and O’s on
each side of the arrow.
2. Classify the reaction that occurred between the iron and oxygen.
Hint: Is something being produced? Choices: Synthesis,
Decomposition, Single Replacement, Double Replacement.
3. What evidence was there that a reaction took place?
Hint: What were your observations?
Part II:
Decomposition of hydrogen peroxide
Part II Materials
• hydrogen peroxide
• small pieces of raw potato (yeast or beef liver may be substituted for the
potato)
• small bowl
Part II:
Decomposition of hydrogen peroxide
Part II: Procedure
• Pour one third of a cup of hydrogen peroxide into a small bowl.
• Cut up several small pieces of raw potato and place them in the hydrogen
peroxide.
• Record your observations.
Part II Questions and Conclusions
Decomposition of hydrogen peroxide
1. The potato (as well as the yeast and beef liver) contains an enzyme called
catalase, which breaks down hydrogen peroxide. Balance the equation, if
necessary, for the breakdown of hydrogen peroxide.
H2O2  H2O + O2
Hint: There must me the same number of H’s and O’s on
each side of the equation.
2. Classify the reaction that occurred as hydrogen peroxide was broken down.
Hint: The words “broken down” gives a clue! Choices: Synthesis
Decomposition, Single Replacement, Double Replacement.
3. What evidence was there that a reaction was taking place?
Hint: What were your observations?
Part III:
Reaction between zinc and acetic acid
Part III Materials:
• a penny dated after 1983
• metal file or coarse sandpaper
• vinegar
Part III:
Reaction between zinc and acetic acid
Part III Procedures
• Use a file or sandpaper to completely remove the copper from the
edge of a penny. Once the copper is removed you can see the
silvery zinc that composes the core of the penny.
• Place the penny into a small jar of vinegar so that the penny sits
upright. This will allow the hydrogen gas to readily escape and
increase the rate of reaction.
• Allow the container to stand undisturbed for 30 minutes.
• Record your observations.
Part III:
Reaction between zinc and acetic acid
Rub the surface off of the
penny with sandpaper or a
nail file.
Make sure you leave it
undisturbed in the vinegar
for at least 30 minutes, maybe
longer.
Part III Questions and Conclusions
Reaction between zinc and acetic acid
1. Balance the equation, if necessary, for the reaction between zinc
and acetic acid.
Zn + CH3COOH  Zn(CH3COO)2 + H2
Hint: There must be the same number of Zn’s, H’s, C’s, and O’s
on each side of the arrow. Don’t forget to distribute the 2
to all of the atoms inside the parenthesis.
2. Classify the reaction between zinc and acetic acid.
Hint: Is it a single or double replacement reaction?
3. What evidence was there that a reaction was taking place?
Hint: What were your observations?
Part IV:
Reaction between magnesium sulfate and
ammonia
Part IV Materials
• Epsom salts (MgSO4)
• ammonia (NH4OH)
• small jar or cup
• measuring cup
Part IV:
Reaction between magnesium sulfate and
ammonia
Part IV Procedures
• Dissolve 1 teaspoon of Epsom salts in a half cup of water.
• Add 2 teaspoons of ammonia to the Epsom salts solution and stir
thoroughly. Record your observations.
• Allow the mixture to stand for 30 minutes and record your
observations.
Part IV Questions and Conclusions
Reaction between magnesium sulfate and ammonia
1. Balance the equation, if necessary, for the reaction between magnesium
sulfate and ammonia.
MgSO4 + NH4OH  (NH4)2SO4 + Mg(OH)2
Hint: There must be the same number of Mg’s, (SO4 )‘s, (NH4)’s and (OH)’s on
each side of the arrow.
2. Classify the reaction between magnesium sulfate and ammonia.
Hint: Is it a single replacement or a double replacement?
3. What evidence was there to indicate that the Epsom salts and ammonia
reacted?
Hint: What were your observations?