One Mole

Description

One mole of each of many different substances are put in plastic sacks and displayed on a bulletin board to demonstrate that moles of different substances can have different masses and volumes.

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Do not to open plastic bags.

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1. Place one molar quantities of each substance in plastic bags.
2. Have students observe and discuss.

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Name ___________________________ Class ________

Teacher__________________________

DoChem 017 One Mole

Watch the slides by stepping through the movie. The small baggies are 1 pint or sandwich size.

Observe the relative volumes of different substances.

1. Which substance displayed has the largest volume/mole? Why?
2. Name another substance you expect to occupy a similar volume/mole.
3. Which is larger a mole of water or a mole of MgO?
4. Describe the volume of a mole of sulfur in your own words.

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Purpose

To show one mole of each of many different substances.

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Store the samples in locking plastic sacks.

• 1 mole Cu (63.5 g)
• 1 mole C (12.0 g)
• 1 mole S (32.1 g)
• 1 mole Pb (207 g)
• 1 mole N₂ (dinitrogen; 28 g)
• 1 mole NaCl (58.5 g in a jar)
• 1 mole sucrose (C12H22O11, 342.0 g)
• 1 mole CaCO₃ (100 g)
• 1 mole NaH₂PO₄ (120 g)
• 1 mole FeSO₄•7H₂O (298 g)
• 1 mole H₂O (18.0 g in a jar)
• 1 mole MgO (40 g)
• 1 mole CuSO₄•5H₂O (249.6 g)
• 1 mole CuCl₂•2H₂O (171 g)

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The containers may be pinned to a bulletin board for display. Note that some of these samples are nearly a pound and will require firm support.

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Teacher preparation: 5 minutes - 2 hours

Presentation: 10 minutes

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There are no unusual hazards in this experiment.

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No special precautions are required in this experiment. Follow routine laboratory precautions. Caution students not to open plastic bags. Select only nontoxic materials which are safely disposed of at the sink or with ordinary solid waste to put into the plastic containers.

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Keep for display from year to year. Store the sacks in a sealable plastic bucket. Replace the locking plastic bags as needed.

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1. Place one molar quantities of each substance in plastic bags.
2. You may prefer to use stoppered wide mouth jars or flasks.
3. Have students observe and discuss.
4. When the materials selected are not hazardous, one excellent way to use mole quantities is to pass them among the students. They may be tacked on bulletin boards. Sodium chloride, sucrose, iron filings, sulfur, copper, magnesium oxide, and water are candidates for plastic bags. Demand courtesy and respect from students for one another during the time that bags are being passed through the classroom.
5. You may wish to have groups of students prepare a one mole bag of an inexpensive substance like water or sucrose. Groups may compare their bags.

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Students have trouble understanding the concept of the mole as a number. Seeing samples of common elements in molar quantities illustrates the differences in size of atoms, densities, and distances between particles in different phases. Stress the idea that each element sample contains the same number of particles (6.02 x 10²³). The number of moles in any sample of a substance can be determined by dividing the mass of the sample by its molar mass. Likewise, the number of particles in a sample can be determined by multiplying the number of moles by Avogadro's number (6.02 x 10²³) and by the integer representing the total number of atoms per formula unit.

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1. Nitrogen or Dinitrogen is largest because it is the only gas. Gases have small intermolecular interactions.
2. Any gas could be named. Oxygen, Hydrogen, etc.
3. MgO
4. Many possible descriptions.

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• element
• mole
• molar mass
• compound
• substance
• Avogadro's number
• water of hydration
• 6.02 x 10²³

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