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Corrosion in Motion (1 Favorite)

LAB in Chemical Change, Chemical Change. Last updated May 30, 2017.


Summary

In this lab, students will expose metal samples to various solutions and observe the amount of corrosion of a period of time.

Grade Level

High or middle school

Objectives

By the end of this lab, students should be able to

  • explain the chemical change of corrosion.
  • apply their observations to real-world examples.

Chemistry Topics

This lesson supports students’ understanding of

  • chemical change

Time

Teacher Preparation: 1 hour

Lesson: 4 class periods (amount of time varies during each meeting)

Materials

Per group

  • gloves
  • electronic balance
  • 16 large test tubes
  • large test tube stand
  • wax pencil
  • 10 mL graduated cylinder
  • Tweezers/forceps
  • 10 mL solution samples (distilled water, salt water, vinegar, cola)
  • metal samples (copper, iron, zinc, aluminum)
  • paper towel

Safety

  • Always wear safety goggles when handling chemicals in the lab.
  • Students should wear gloves during the lab, as some chemicals can cause skin irritation.
  • Students should wash their hands thoroughly before leaving the lab.
  • When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.
  • Turn on the exhaust fan in the lab, or use a ventilation hood.

Teacher Notes

  • For middle school students you may want to premeasure the solutions.
  • To perform this lab on a smaller scale, choose fewer solutions depending on what you are studying. To explore control and variables, use distilled water and one other solution.
  • Differentiation for higher level students:
    • calculate the rate of corrosion.identify type of chemical reactions occurring.
    • show balanced equations of reactions.
    • apply concepts of oxidation and reduction.
  • Some links for related articles, these could be used pre-lab or post-lab:
  • The teacher can create the salt water solution beforehand by dissolving several grams of salt in water. The high level students you can ask them to calculate and make a certain molarity value for the salt water solution.
  • The metal samples listed are suggestions, and can be switched for other metals you may have on hand. Metal wire or scrap metal will work well. It is not necessary for each group to have the same amount of metal.
  • The first class meeting will take the longest; students will collect the most data this day. Each observation day will take 2-30 minutes. The final day will also take longer, to allow for students to answer the analysis questions.

For the Student

Background

Corrosion is the breakdown of a material when exposed to water or air. It is a chemical change that weakens the material. A common example of corrosion is rust. Rusting is the corrosion of the metal iron.

Prelab Question

What are some examples of corrosion?

Materials

Per group

  • electronic balance
  • 16 large test tubes
  • large test tube stand
  • wax pencil
  • 10 mL graduated cylinder
  • Tweezers/forceps
  • 10 mL solution samples (distilled water, salt water, vinegar, cola)
  • metal samples (copper, iron, zinc, aluminum)
  • paper towel

Safety

  • Always wear safety goggles when handling chemicals in the lab.
  • Wear gloves during the lab, some chemicals can cause skin irritation.
  • Wash your hands thoroughly before leaving the lab.
  • Follow your teacher’s instructions for cleaning up materials and disposal of chemicals.

Procedure

Experiment Set-up Procedures (Day 1)

  1. Label your test tubes using the wax pencil, include the solution name and the metal to be placed in tube. For example:
    1. Aluminum + Distilled Water
    2. Aluminum + Salt Water
  2. Organize tubes in rack, replicating the layout of data table.
  3. Obtain four samples of each metal.
  4. Record the initial appearance of each metal in the “Metal Appearance” data table for day 1.
  5. Find the mass of each metal sample. Record the mass of each metal in the designated data table, and then place the metal sample in the corresponding empty test tube.
  6. Add 10mL of each solution into the four corresponding test tubes.
  7. Follow you teacher’s instructions for setting the test tube tray in a designated place until the next observation day.

Observation Day Procedures (Repeat Days 2-4)

  1. Using tweezers/forceps and wearing gloves, carefully remove a metal sample from the test tube. Pat dry with paper towel.
  2. Examine the sample. Record appearance on the data sheet for “Metal Appearance” for the corresponding observation day.
  3. Place each sample on the balance to obtain the mass value. Record the mass on data sheet.
  4. Return sample to test tube. Repeat with each sample.

Data
Examples are shown below. Refer to the Data Sheet for complete data tables.

Metal Mass Initial (Day 1) Mass Day 2 Mass Day 3 Mass Day 4
Aluminum and distilled water
Aluminum and salt water
Aluminum and vinegar
Aluminum and soda
Aluminum Metal Sample Mass
Record the mass of each metal sample during each day of the experiment.
Metal Mass Initial (Day 1) Mass Day 2 Mass Day 3 Mass Day 4
aluminum
copper
iron
zinc
Metal Appearance
Describe the original appearance of each of the samples.

Analysis

  1. List the three main components necessary for corrosion to occur. Include their source.
  2. Would you predict stainless steel to rust? Why? Why not?
  3. Identify the acid from the solutions you used. What outcome was observed from this substance?
  4. Applying what you have observed, explain two ways in which corrosion has an effect on our everyday lives. What are some ways in which we can prevent this?