The Mole and Avogadro’s Number
Friday, July 23rd, 2010 at
2:12 pm
Introduction to the idea of a mole as a number (vs. an animal)
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Tagged with: avogadro's • chemistry • mole • number
Filed under: Wart Removers
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oh thank u man! i’m italian but i’ve understood more your lesson than my teacher’s one…
definitions in wiki is so confusing to work with
@polos505 if you see this in a question in a text, see if it is a molecule of H (2H) or just an atom H (1H).
the same would apply to O and any other diatomic molecules such as N of the halogens.
Thank you for much sir for your time and videos, I get so much use out of them. Your videos have helped me so much, but i’m still having little trouble with using moles as unit of mesurment, can you please make another video about it!! Please!!!
that’s gr8 i now can work out the prob
dude I am bengali too great lesson keep it up.
ahhahahah students in kosovo we learn all this in the 7th classand avogadros law or rule
we learn very much
thnx khan…ur video really helps me especially in the concept of mole..better than my teacher…great job…:)
Are you confusing atomic mass for atomic number? Aluminum has an atomic mass of 26.98.
@khanacademy U speak urdu? kaise ho?
thanx bro. needed this 4 ma igcse. keep doin wat u doin
THANK YOU SO MUCH!!!!!!!!
hey sal can you do a video about dimensional analysis
This video has helped me so much, thank you sooooooo much!!! I will sure be watching more of your videos
oh wow! my chemistry teacher is horrible and no one ever understood moles, now its sooo easy! thank you sooo much!
I really value your videos, you’re the best chemistry teacher I’ve ever had. I’m an IB student and could really need some help with understanding the steps taken to solve chemical equations, mass and gaseous relationships, and molar volume of a gas and those types of calculations. You’re the best!
hey idk who u are but u helped me alot with understanding this new languauge. thanks for dedicating the time to help those in need. thank u
so how do you know that is true?
how do you know there are 6.02 x 10^23 atoms in one gram of carbon? It’s not like you can count each individual atom, so how do you know avagadros # is true?
thank you for speaking clearly and helping me understand this so much better. keep up the good work!
nice job!!!!!!
@brianmenendez
The first part:
Accurate determinations of Avogadros number require the measurement of a single quantity on both the atomic and macroscopic scales using the same unit of measurement. This became possible for the first time when American physicist Robert Millikan measured the charge on an electron. The charge on a mole of electrons had been known for some time and is the constant called the Faraday.
@brianmenendez
The second part;
The best estimate of the value of a Faraday, according to the National Institute of Standards and Technology (NIST), is 96,485.3383 coulombs per mole of electrons. The best estimate of the charge on an electron based on modern experiments is 1.60217653 x 10-19 coulombs per electron. If you divide the charge on a mole of electrons by the charge on a single electron
@brianmenendez
The third part;
Another approach to determining Avogadro�s number starts with careful measurements of the density of an ultrapure sample of a material on the macroscopic scale. The density of this material on the atomic scale is then measured by using x-ray diffraction techniques to determine the number of atoms per unit cell in the crystal and the distance between the equivalent points that define the unit cell (see Physical Review Letters, 1974, 33, 464).
@nbableful the third part sounds the most accurate
this is the only video that made me understand. thank you so much