Chemical Quantities - The Mole
Chalk, Penny, and Sugar Cube Lab
Part 1: You will be given a pre-1982 penny, a piece of chalk, and a sugar cube. You are to find the number of representative particles in each item. If you feel you need more information, you need to ask me. For this part, write your own procedure, data table, and show your calculations.
Part 2: After you have found the number of particles in the chalk, write your answer on the board. Now find the number of particles of chalk you left on the board. Write your procedure, data, and show your calculations.
Part 3: Calculate the percent uncertainty in your penny value from part 1.
No other parts of a write-up are needed.
Aluminum Foil Thickness Lab
How thick is aluminum foil in centimeters? How many atoms thick is this? The small size of any one atom gives a clue to the relatively large number of atoms in a sample of matter that we can pick up and measure. The size of an aluminum atom was measured by a process called x-ray diffraction and found to be about 2.5 x 10-8 cm long. The purpose of this activity is to relate the size of an aluminum atom to the thickness of a piece of aluminum foil.
In order to find the thickness in terms of atoms you will need to know the density of aluminum, 2.70g/cm3, and compute the thickness of your piece of foil. Before you come into lab write a short introduction, hypothesis (how many atoms thick do you think a piece of Al foil is and why), copy the procedure below, write a data table, then copy the calculations table.
Procedure:
- Obtain a square piece of Al foil approximately 12 cm x 12 cm.
- Measure and record the length and width of the foil to the nearest 0.1 cm.
- Find the mass of the foil. Return the foil to the proper place.
Data Analysis:
Calculations:
For the calculations, copy the table below. Show your work for calculations and record the answers in the table.
- Density of Al _________
- Mass of Al foil _________
- Volume of foil (cm3) _________
- Height of foil (cm) _________
- Atoms thick of the foil _________
- Moles of Al in foil _________
- Atoms of Al in foil _________
C. Use the density and the mass to find the volume.
D. To find the thickness (H), you know that V= L x W x H. Using other information in your data table, find H.
E. One aluminum atom is 2.5 x 10-8 cm thick. Find the thickness in atoms using the height.
F. Knowing the mass of your foil, find the moles of Al.
G. Knowing the moles of Al, find the total number of atoms in the foil.Question:
If the population of the world is 5.6 x 109 individuals, how many atoms of aluminum could you distribute to each person from your sample of aluminum foil?
Evaluation: As usual.
Conclusion: As usual.