Safety Reminder: Wear Safety Glasses and Use Ammonia in a Well-Ventilated Area

Classifying Reactions

Safety Reminder: Wear safety glasses and use ammonia in a well-ventilated area.

Objectives:

•Identify different types of chemical reactions

•Predict the products of reactions

•Understand and balance chemical equations

PART 1

Materials:

small glass jars

dish with sides (a pie plate works well)

steel wool

water

Procedures

1.Tape a piece of steel wool to the bottom of the jar.

2.Fill the dish about halfway with water.

3.Put the jar upside down in the dish.

4.Observe the water levels in the jar for five days. Record your observations.

5.Observe the steel wool in the jar for five days. Record your observations.

Observations:

Day

Water Level in Dish (cm)

Water Level in Jar (cm)

Appearance of Steel Wool

2

1

3

4

5

Analysis/Conclusion:

1.Balance the equation, if necessary, for the reaction between iron and oxygen.

Upper F e plus Upper F e plusUpper F e plus Upper O subscript 2 baseline right arrowUpper O subscript 2 baseline right arrow Upper O subscript 2 baseline right arrow Upper F e subscript 2 baseline upper O 3 Upper F e subscript 2 baseline upper O 3 baselineUpper F e subscript 2 baseline upper O 3 baselineUpper F e subscript 2 baseline

upper O 3 2.Classify the reaction that occurred between the iron and oxygen.

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3.What evidence was there that a reaction took place?

PART 2

Materials:

hydrogen peroxide

small pieces of raw potato (yeast or beef liver may be substituted for the potato)

small bowl

Procedures

1.Pour one third of a cup of hydrogen peroxide into a small bowl.

2.Cut up several small pieces of raw potato and place them in the hydrogen peroxide.

3.Record your observations.

Observations:

Appearance of potato and hydrogen peroxide combination

Analysis/Conclusion:

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 following reaction.

Upper H subscript 2 baseline upper O right arrowUpper H subscript 2 baseline upper O right arrowUpper H subscript 2 baseline upper O right arrowUpper H subscript 2 baseline upper O right arrow Upper H subscript 2 baseline upper O right arrowUpper H subscript 2 baseline upper O right arrow Upper H subscript 2 baseline upper O plusUpper H subscript 2 baseline upper O plusUpper H subscript 2 baseline upper O plusUpper H subscript 2 baseline upper O plusUpper H subscript 2 baseline upper O plusUpper O subscript 2 baselineUpper O subscript 2 baseline

2.Classify this reaction that occurred.

3.What evidence was there that a reaction was taking place?

PART 3

Materials:

a penny dated after 1983

metal file or coarse sandpaper

vinegar

Procedures

1.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.

2.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.

3.Allow the container to stand undisturbed for 30 minutes.

4.Record your observations after 30 minutes.