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When you have completed all of your measurements, rinse your syringe with pure hexane, and dispose of all the hexane-containing solutions in the waste collection bottle provided.
Calculation Of Avogadro's Number
The calculation proceeds in several steps.
Initial Lab: Avogadro and All ThatReport 1
Note: In preparing this report you are free to use references and consult with others. However, you may not copy from other students’ work (including your laboratory partner) or misrepresent your own data (see honor code).
Name(Print then sign): ___________________________________________________
Lab Day: ___________________Section: ________TA__________________________
Note: In preparing this report you are free to use references and consult with others. However, you may not copy from other students’ work (including your laboratory partner) or misrepresent your own data (see honor code).
Demonstrations:
Balloons:
Thermite:
Include description and relevant equation: ${\text{Fe}}_{2}{\text{O}}_{3}\text{+ Al}\to $
Dry Ice and Magnesium:
Include description and relevant equation: $\text{MgO + C}\to $
1. Identification of Apparatus
2. Balance Use
3. Measuring the volume of a liquid
From a consideration of the masses of water measured above, and given that the density of water is 1 g/mL, decide on an order of which is the most accurate method of volume measurement – measuring cylinder, pipette, or burette with (1) being the most accurate?
(1)
(2)
(3)
How precisely could each of the apparatus used be read?
(1) measuring cylinder
(2) pipette
(3) burette
4. Estimation of Avogadro's Number
Measurement of the volume of stearic acid solution required to cover the water surface
Trial 1 | Trial 2 | |
Record the diameter of the water surface | ___________________ | ___________________ |
Record the volume of stearic acid solution required to cover the surface | ___________________ | ___________________ |
Record the concentration of the stearic acid solution | ___________________ | ___________________ |
Calculation Of Avogadro's Number
a. Calculation of the thickness of a monolayer of stearic acid
Trial 1 | Trial 2 | |
From your data, the volume of stearic acid solution required to form a monolayer was | ___________________ | ___________________ |
Calculate the mass of stearic acid contained in that volume of stearic acid solution (the concentration in grams per liter will be given to you) | ___________________ | ___________________ |
Calculate the volume, V, of pure stearic acid in the monolayer on the water surface. You will need the density of solid stearic acid, which is 0.85 g/ml (or ${\text{g/cm}}^{3}$ ). | ___________________ | ___________________ |
Calculate the area of the monolayer (A = ${\mathrm{\pi r}}^{2}$ , r is the radius of the water surface) | ___________________ | ___________________ |
Calculate the thickness of the monolayer (t = Volume/Area) | ___________________ | ___________________ |
b. Estimation of the size and volume of a carbon atom
Trial 1 | Trial 2 | |
A stearic acid molecule consists of 18 carbon atoms linked together. Assuming that the thickness, t, of a monolayer is equal to the length of the stearic acid molecule, calculate the size of a carbon atom, s = t/18 | ___________________ | ___________________ |
Assuming that a carbon atom is a little cube, calculate the volume of a carbon atom, volume = ${s}^{3}$ | ___________________ | ___________________ |
c. Calculation of the volume of a mole of carbon atoms
Trial 1 | Trial 2 | |
Calculate the molar volume of carbon (diamond) by using the density of diamond $(3\text{.}{\text{51g/cm}}^{3}$ ) and the atomic mass of a mole of carbon | ______________________________ | _______________ |
Is the volume of a mole of diamond the same as the actual volume of a mole of carbon atoms? | ______________________________ | _______________ |
d. Calculation of the volume of a mole of carbon (diamond) volume of a single carbon atom (Avogadro's number)
Trial 1 | Trial 2 | |
Calculate Avogado's number (NA) from the appropriate ratio of volumes | _________________________________ | _____________ |
Calculate the average value of NA from your results | _________________________________ | _____________ |
Express your results as a number ${\text{10}}^{\text{23}}$ . Are you within a power of 10 of the accepted value of 6.02 ${\text{10}}^{\text{23}}$ ? | ________________________________ | _____________ |
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