Measuring Changes in Mass In this task, you’ll analyze the metal strips from test tubes 1 and 5 in task 1 to determine what kinds of changes occurred to them. If you need a refresher on using the electronic balance, watch this video about measuring mass.

Estimated time to complete: 45 minutes

If you’ve purchased an Edmentum lab kit, remove the items that appear in the equipment list. You’ll also need distilled or tap water and paper towels for cleanup.

You’ll need these materials:
electronic balance
Erlenmeyer flask
funnel
filter paper
wash bottle with distilled water (tap water is acceptable but may skew experimental results)
forceps
test tube brush
apron
goggles
gloves
paper towels
Always work safely:
Keep lids on the chemical bottles at all times, except when you’re actively dispensing from a bottle.
Wear an apron, goggles, and gloves anytime you’re working with chemicals, including during disposal procedures.
Don’t mix chemicals together except as instructed in the laboratory procedure.
If a chemical splashes into your eyes, immediately remove any contact lenses and flush your eyes with running water for at least 15 minutes. Seek medical attention.
To begin the task, follow these steps. Then proceed to part A.

Use forceps to remove the metal strip from test tube 1. Rinse the strip with water, and set it on a paper towel to dry.
Use forceps to remove the metal strip from test tube 5. Rinse the strip with water, and set it on a paper towel to dry.
Part A
Weigh the mass of the dried metal strips from test tubes 1 and 5 using the electronic balance. Record their masses in the table.

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Part B
Compare the mass of the magnesium strip from test tube 1 with the initial mass of the same strip measured in task 1, part A. Is the mass the same, or is it different? If it’s different, explain what may have caused the difference.

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Part C
Compare the mass of the zinc strip from test tube 5 with the mass of the same strip measured in task 1, part A. Based on your observations of the metal strip, explain what factors may have added to its mass or caused a decrease in its mass. Which had the greater effect? Explain your reasoning.

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Part D
What evidence can be used to support the fact that oxidation, reduction, or both took place in test tube 5?

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Cleanup and disposal: Wear your goggles, apron, and gloves during cleanup.
Discard the metal strips from test tubes 1 and 5 in the trash.
Slowly pour the solution from test tube 1 down the sink drain along with plenty of running water. Rinse the test tube with distilled water, and return it to the rack to dry.
The solid must be filtered out of test tube 5 before disposal. Set up the Erlenmeyer flask, funnel, and filter paper for filtration. Use this filtration technique to collect the solid waste. Once the filtration is complete, dispose of the filter paper (and the solids in it) in the trash, and pour the filtered liquid down the sink drain with running water. Rinse the test tube with distilled water. If sediment remains in the test tube and can’t be rinsed out with water, clean the insides with the test tube brush, and then perform a final rinse with distilled water.