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Honors Chem: Moles in Real Life Lab

Last updated about 2 years ago
20 questions

Background:

Imagine trying to purchase fruit without being able to count the number or measure the mass of the pieces you choose. Sounds difficult, doesn’t it? Every day people perform a variety of tasks that require the ability to count or measure. In some cases, the job is easier than in others – but it is always important.

Counting atoms, like counting sand particles, is no easy task! Perhaps you are wondering if it is even possible, considering how very small atoms are. The answer is yes, but you do not count the number of atoms as you might count marbles in a box. Over the past 50 years, scientists have devised many direct and indirect methods for determining this number using sophisticated equipment. To find the number of atoms in a given mass of an element, chemists decided to use the element carbon as a standard. The number of atoms in 12.0 grams of carbon-12 was determined experimentally. From such experiments, it was found that the number of atoms of an element whose mass in grams is numerically equal to its atomic mass is 6.02 x 1023. This number is Avogadro’s number.

The mole establishes a relationship between the atomic mass unit and the gram. The mole might seem to be a strange term, but the concept is not. Every day you encounter many items that are usually packaged together and described as a group. Like dozen, gross, or ream, it is convenient to have a special name to describe a group of atoms. The group in chemistry is the mole, and it contains 6.02 x 1023 items.
In this experiment, you will investigate the relationship between particles, mass, and moles of four items used in our daily lives. In doing so, you will have a better understanding of how the small size of any one atom gives a clue to the relatively large number of atoms in a sample.

Materials:
Chemicals Equipment
Aluminum Foil Electronic balance
Pre-1982 Penny Ruler
Sugar Cube Construction Paper
Chalk
Procedure:

1. Measure and record the mass of a penny, sugar cube, piece of chalk, and aluminum foil sample.

2. Write or draw with the chalk on a piece of construction paper. Make sure that your writing or drawing is appropriate for school. Please have each member in the group sign their name.

3. Measure and record the mass of the chalk again.

4. Measure and record the length and width of the aluminum foil to the nearest 0.10 cm.

5. Return all samples to the designated area.
1

DATA Table to fill out.

Calculations:
· Show all steps of your calculations in the space provided.
· Units should be carried through each step of the calculation.
· Your answer should be reported to the proper number of significant figures.
· Box your final answer.
Required
1

Determine the number of moles of copper in the penny.

Required
1

Determine the number of atoms of copper in the penny.

Required
1

Determine the molar mass of sugar (C12H22O11).

Required
1

Determine the number of moles of sugar in the sugar cube.

Required
1

Determine the number of molecules of sugar in the sugar cube.

Required
1

Determine the mass of chalk left on the piece of construction paper. (The amount of chalk used to write.)

Required
1

Determine the molar mass of chalk, calcium carbonate (CaCO3).

Required
1

Determine the number of moles of calcium carbonate left on the piece of construction paper.

Required
1

Determine the number of formula units (particles) of calcium carbonate left on the piece of construction paper.

Required
1

Using the site: Aluminum | Al - PubChem (nih.gov), record the density of aluminum.

Required
1

Determine the volume of the aluminum foil sample.

Required
1

Determine the thickness of the aluminum foil sample.

Required
1

Determine the number of moles in the aluminum foil sample.

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1

Determine the number of atoms in the aluminum foil sample.

Required
1

If one atom of aluminum is 2.5 x 10-8 cm thick, how thick is your aluminum foil in atoms?

Extension:
· Please show any calculations and work where applicable and answer in complete sentences.
Required
1

If the population of the world is 7.9 x 109 individuals, how many atoms of aluminum could you distribute to each person from your sample of aluminum foil?

Required
1

If you were to multiply the volume of aluminum by three, how would this change the number of molecules of aluminum? Explain your answer.

Required
1

The composition of the penny changes after 1982. It is now made of a zinc core surrounded by copper. How would this change how you would calculate the moles and atoms in a penny?

Required
1

Explain how you would determine the number of molecules of added sugar you ate at lunch.