Lab: Estimating Avogadro's Number This laboratory has you using two different methods to determine Avogadro’s Number. View the Estimating Avogadro's Number power point attached below and then view the...

Estimating Avogadro’s Number
Laboratory Report
Activity 1: Determination of Avogadro’s Number Using Stearic Acid
Monolayer
Data Table
Use the information entered into Data Table 1 in the Investigation Manual to complete the table
elow. Items in BOLD are data collected during completion of the experiment. Asterisks (*) are
calculated values. Showing the work for some of the calculations is required (Activity 1
Questions/ Calculation Examples).
Measurements Trial 1 Trial 2
Length of Thread Used (cm) as described in
Step 6
Measure after loop is made, this is the circumference
of the circle.
6.5 6.54
*Radius of Loop (cm)
Use: Circumference = 2ϖr where ϖ = 3.14
4.0 4
*Area of Loop (cm2)
Use: Area = ϖr2 where ϖ = 3.14
12.56 12.56
Initial Volume of Stearic Acid Solution in
Syringe (mL)
1 1
Final Volume of Stearic Acid Solution in Syringe
(mL)
0 0
*Volume of Stearic Acid Dispensed (mL)
Use: (initial volume – final volume)
1 1
Concentration of Stearic Acid 0.1 g/L 0.1 g/L
*Mass of Stearic Acid (g)
Use: volume(L) x concentration
2.6g 2.8g
*Moles of Stearic Acid (mol)
Use: Mass(g) x 1 mol/284.5 g
0.91 x 10 2 0.98 x 10 2
Area of Stearic Acid in loop (cm2)
Use: Area of Stearic Acid = Area of Loop (already
determined)
12.56 12.56
Area of one Stearic Acid Molecule (cm2) 20.7 x 10-16 cm2 20.7 x 10-16 cm2
Number of Stearic Acid Molecules in Loop
Use: Area of Stearic Acid in Loop/Area of 1 Stearic
Acid Molecule
1.64 x 10 14 1.64 x 10 14
Avogadro’s Number
Use: Number of Stearic Acid Molecules/Moles of
Stearic acid)
1.811 x 10 12 1.8111 x 10 2
Avogadro’ Number (Average Value of the two Trials) 1.811 x 10 12
Percent E
or (%) (Based on Average Value) 23
Activity 1 Questions/Calculation Examples
1. (0.5 points) Show the calculation below of the area of the thread loop used in Trial 1 as
illustrated on Page 5 of the Investigation Manual. This co
esponds to the calculation
equired for the ‘Area of Loop’ in the table above.
Area of Loop (cm2)
Area = ϖr2 where ϖ = 3.14, = 3.14*4*4 = 50.24 cm2
2. (0.5 points) Show the calculation below of the mass of stearic acid used to form the
monolayer in Trial 1 as illustrated on Page 5 of the Investigation Manual. This
co
esponds to the calculation required for the ‘Mass of Stearic Acid’ in the table above.
Mass (in grams) of one mole of stearic acid 1 mole = 284.48 g/mol
3. (0.5 points) Show the calculation below of the number of moles of stearic acid in Trial 1
as illustrated on Page 5 of the Investigation Manual. This co
esponds to the calculation
equired for the ‘Moles of Stearic Acid’ in the table above.
Moles of Stearic Acid (mol)
Use: Mass(g) x 1 mol/284.5 g = 0.91 x 10 2
4. (0.5 points) Show the calculation below of the number of stearic acid molecules in the
monolayer in...