# Initial lab: avogradro and all that  (Page 4/4)

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.

The calculation proceeds in several steps.

• We calculate the volume of stearic acid solution in hexane required to deliver enough stearic acid to form a monolayer.
• All of the hexane evaporates, leaving only the thin monolayer film of stearic acid, so we next calculate the actual mass of pure stearic acid in the monolayer.
• We calculate the thickness of the stearic acid monolayer, using the known density of stearic acid and the area of the monolayer.
• Assuming the stearic acid molecules are stacked on end and are tightly packed, and knowing that there are 18 carbon atoms linked together in the stearic acid molecule, calculate the diameter and volume of a carbon atom.
• Calculate the volume of a mole of carbon atoms in diamond; divide the molar volume of carbon (diamond) by the volume of a single carbon atom to obtain an estimate of Avogadro's number. Remember that the units of Avogadro’s number are mol-1, so you can use unit analysis to check your answer.

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:

• Oxygen

• Hydrogen
• Mixture of Hydrogen and Oxygen with relevant equation: ${H}_{2}{\text{+ O}}_{2}\text{}\to$

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

• beaker

• pipette

• burette

• Bunsen burner

• test tube
• watch glass

2. Balance Use

• Mass of weighing paper and solid, ________ g
• Mass of weighing paper, __________ g
• Mass of solid, ___________g
• Mass of solid on tared weighing paper ____________g

3. Measuring the volume of a liquid

• Mass of 50 mL beaker and water, g ______________
• Mass of 50 mL beaker, g ______________________
• Mass of water from graduated cylinder, g___________
• Mass of 50 mL beaker and water, g ______________
• Mass of 50 mL beaker, g ______________________
• Mass of water from pipette, g ____________________
• Mass of 50 mL beaker and water, g ______________
• Mass of 50 mL beaker, g ______________________
• Mass of water from burette, g ____________________

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

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 ___________________ ___________________

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 $\left(3\text{.}{\text{51g/cm}}^{3}$ ) 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 ${\text{10}}^{\text{23}}$ ? ________________________________ _____________

find the 15th term of the geometric sequince whose first is 18 and last term of 387
I know this work
salma
The given of f(x=x-2. then what is the value of this f(3) 5f(x+1)
hmm well what is the answer
Abhi
how do they get the third part x = (32)5/4
can someone help me with some logarithmic and exponential equations.
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
hmm
Abhi
is it a question of log
Abhi
🤔.
Abhi
I rally confuse this number And equations too I need exactly help
salma
But this is not salma it's Faiza live in lousvile Ky I garbage this so I am going collage with JCTC that the of the collage thank you my friends
salma
Commplementary angles
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
hii
Uday
hi
salma
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
a perfect square v²+2v+_
kkk nice
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
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Kristine 2*2*2=8
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. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
what's the easiest and fastest way to the synthesize AgNP?
China
Cied
types of nano material
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
Uday
what is nanomaterials​ and their applications of sensors.
what is nano technology
what is system testing?
preparation of nanomaterial
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
what is system testing
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
how did you get the value of 2000N.What calculations are needed to arrive at it
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